Technical articles

From Spectral Mismatch to Device Gain: Key Mechanisms, Experimental Guidance, and Aladdin Material Selection for Lanthanide Upconversion and Downconversion (Quantum Cutting) in Solar Cells

Solar-cell efficiency is limited not only by whether the material is “good,” but also—crucially—by spectral mismatch losses arising from the mismatch between the solar spectrum and the cell bandgap (Eg):

  • High-energy photons (E  Eg): after absorption, photogenerated carriers rapidly relax to the band edges, and the excess energy is mainly dissipated as heat (carrier thermalization).
  • Low-energy photons (E < Eg): these photons are difficult to absorb and often transmit through the device, generating no current.
  • Under the detailed-balance (Shockley–Queisser) framework for single-junction solar cells, unavoidable losses such as thermalization + transmission constrain the efficiency limit to roughly 30–33%: early classic derivations often yielded values on the order of ~30%, while under the AM1.5G standard spectrum a commonly cited peak is ~33.16% (optimal bandgap ~1.34 eV).

The purpose of spectral conversion is to convert “less useful photons” into photons that are better matched to bandgap absorption before light enters the solar cell, thereby reducing spectral mismatch losses. Lanthanide ions (predominantly Ln³, with a small number of systems involving Ln²) are important candidates for such “photon management” because of their unique 4f energy-level structures.

Comparison of Spectral-Conversion Strategies: Downshifting, Downconversion (Quantum Cutting), and Upconversion

Category

English

Photon-number relationship

Primary spectral loss addressed

Typical incident/excitation light (examples)

Typical output light (examples)

Recommended placement

Key bottlenecks

Common engineering approaches

Downshifting

Downshifting (Luminescent Downshifting, LDS)

1 → 1

Thermalization loss from high-energy photons: “shift” UV/blue photons to wavelengths more readily absorbed by the cell

UV/blue (broadband)

Visible / NIR (depends on the cell bandgap)

Front side of the cell (front layer)

Parasitic absorption in the layer; escape due to isotropic emission; layer transparency/stability

Choose highly transparent hosts; enhance absorption (allowed transitions/sensitization); refractive-index matching and AR design to reduce escape

Downconversion (Quantum Cutting)

Downconversion / Quantum Cutting

1 → 2 (ideal)

Thermalization loss from high-energy photons: split “excess energy” into two photons closer to Eg

UV/visible (depends on donor absorption)

Common target: ~1000 nm (Yb³ emission, close to c-Si)

Front side of the cell (front layer)

Absorption remains weak; higher doping often required but prone to concentration quenching; emission escape reduces usable photons at the device

Donor–acceptor level matching (e.g., Tb → 2Yb, Pr → Yb, etc.); low-phonon-energy hosts; optical coupling/reflective structures to enhance in-coupling and photon capture

Upconversion

Upconversion (ETU/ESA, etc.)

2 → 1

Sub-bandgap transmission loss: combine low-energy NIR photons into higher-energy photons

NIR: commonly 980 nm (Yb sensitization), or 1480–1580 nm / ~1.5 μm (Er-related)

Visible (green/red) or higher-energy NIR

Rear side of the cell (back layer) + back reflector to “send” emission back into the cell (rear-attached designs are common)

Extremely low nonlinear efficiency under low irradiance; narrow absorption bands; surface quenching/OH in nanomaterials

Broadband sensitization (“antenna”); core–shell structures to suppress quenching; cavities/plasmonics/back reflectors to enhance field and coupling (evaluate parasitic absorption and heating)

Why Lanthanide Ions: Strengths and Limitations

Strengths: “Atom-like” 4f levels enable energy-pathway engineering

1. Relatively stable energy levels and sharp-line spectra

  • The 4f electrons of Ln³ are shielded by outer 5s/5p electrons, so their energy levels are relatively less sensitive to the host environment.
  • Typical features include narrow-line absorption/emission and clearly defined energy-level structures.
  • Note: in solids, crystal-field (Stark) splitting still occurs, and a few transitions are more sensitive to local symmetry (lanthanides are not “completely environment-independent”).

2. Many levels and long lifetimes: “programmable” energy transfer

(1) Multi-step energy ladders and long excited-state lifetimes make pathways such as energy transfer, stepwise excitation, and cooperative transfer easier to realize.

(2) This is well suited for designing:

  • Energy addition: Upconversion
  • Energy splitting: Downconversion / Quantum Cutting

Limitations: weak 4f–4f transitions and narrow absorption (not solar-friendly)

1. Root cause: small absorption cross-section + narrow absorption bands

(1) For most Ln³, 4f–4f transition strengths are weak (often described as “quasi-forbidden”), meaning:

  • It is difficult to drive efficiently using broadband sunlight at low power density.
  • Both upconversion and downconversion suffer from an “insufficient absorption” bottleneck.

2. Accordingly, research typically advances along three main directions

(1) Enhancing absorption

  • Sensitizers and broadband “antenna” absorbers (broadening the narrow absorption entrance)

(2) Suppressing non-radiative losses

  • Low-phonon-energy hosts (e.g., fluorides)
  • Control of defects and OH (high-vibration groups strongly quench emission)
  • Core–shell structures in nanomaterials to reduce surface quenching

(3) Increasing “externally usable photons”

  • Refractive-index matching; anti-reflection/reflective structures; layer thickness and optical coupling design
  • Goal: reduce escape caused by isotropic emission, so that more light enters the cell and is absorbed

Photoluminescence Quantum Yields vs Solar-Cell Quantum Efficiencies

Abbrev.

Common English term

Definition (numerator / denominator)

Can it exceed 100%?

Scope / notes

IQY

Internal Quantum Yield / Internal PLQY

Number of photons generated inside the sample / Number of photons absorbed by the sample

Yes (for quantum cutting, the ideal limit approaches ~200%)

Captures the material’s intrinsic photon-conversion capability; preferably measured by absolute integrating-sphere methods, with excitation conditions and the absorptance calculation clearly reported

EQY (or ext-PLQY)

External Quantum Yield / External PLQY

Number of photons emitted out of the sample / Number of photons absorbed by the sample

In principle, yes (if IQY > 100% and light-extraction is not too low)

Includes extraction efficiency, waveguiding/total internal reflection, interface reflection, reabsorption, and scattering; typically closer to the usable output from “sample + optical structure”

EQE (PV)

External Quantum Efficiency

Number of electrons collected by the solar cell / Number of photons incident on the device (wavelength-resolved)

Typically ≤100% for solar cells

Device-side PV metric; used to quantify how much additional photocurrent is obtained after integrating a spectral-conversion layer

IQE (PV)

Internal Quantum Efficiency

Number of electrons collected by the solar cell / Number of photons absorbed by the cell

Typically ≤100%

Evaluates carrier collection after removing optical losses (reflection/transmission); not the same concept as PL IQY

Note: In this table, IQY/EQY are photoluminescence quantum yields (photon/photon), whereas IQE/EQE for solar cells are device quantum efficiencies (electron/photon). Do not mix these two sets of metrics.

Upconversion: Classic Systems and Why It Is “Difficult Under Sunlight”

1. Most common mechanism: Energy-Transfer Upconversion (ETU)

  • ETU (Energy Transfer Upconversion) is one of the most common—and often relatively efficient—lanthanide upconversion pathways. A typical pair is Yb³/Er³⁺: Yb³ has a comparatively stronger absorption band near ~980 nm. After excitation, Yb³ transfers energy to Er³⁺; a second energy-transfer step (often together with processes such as ESA) promotes Er³ stepwise to higher excited states, ultimately producing green/red upconverted emission.
  • For sub-bandgap photon recovery in crystalline silicon, note that c-Si has a room-temperature bandgap of ~1.12 eV, corresponding to an absorption edge near ~1100 nm. Longer-wavelength NIR light (>1100 nm) is largely not absorbed by silicon. Therefore, silicon-oriented UC focuses on converting transmitted NIR beyond 1100 nm into higher-energy photons. In device demonstrations, one often sees systems and test conditions related to ~1.5 μm (Er³-related absorption bands).

2. Why β-NaYF is commonly used: low phonon energy is critical

  • Upconversion relies on multiple excitations and sufficient lifetimes of intermediate states. If the host material has a high phonon energy, multiphonon relaxation dissipates energy more readily, leading to a significant drop in UC efficiency. Thus, low-phonon-energy fluoride hosts are generally advantageous.
  • Within the NaREF family, β-phase (hexagonal) NaYF has long been considered one of the most outstanding UC hosts (and in practice it is often observed that β-phase outperforms α-phase).

3. A key device-level reality: power density at 1 sun is often insufficient

  • Upconversion is intrinsically nonlinear: the lower the excitation intensity, the lower the probability that two (or more) photons can “meet” to complete the UC process. Many “very bright” UC results are obtained under high-intensity monochromatic laser excitation, and directly extrapolating these results to natural sunlight (1 sun) often overestimates practical device gains.
  • In a classic “silicon cell + upconversion layer” demonstration, a device EQE of ~3.4% was reported under 1523 nm monochromatic pumping at 2.4 W/cm² (= 24,000 W/m²). This is an important result, but it also clearly indicates that without optical concentration, absorption broadening, and optical enhancement, significant gains under natural sunlight are typically difficult. (A commonly used 1 sun irradiance level is ~1000 W/m².)

UC vs QC: Why They Are “Difficult Under Sunlight” (Comparison Table)

Dimension

Upconversion UC (2 → 1)

Downconversion / Quantum Cutting QC (1 → 2)

Spectral loss addressed

Sub-bandgap transmission: “lift” low-energy photons that would otherwise pass through the cell

Thermalization loss: split excess photon energy into two photons closer to the bandgap

Key wavelength relationship to c-Si

c-Si absorption edge ~1100 nm; UC targets recovery of transmitted NIR >1100 nm

Yb³ ~1 μm emission (~980–1030 nm; host-dependent shift) is commonly used as a near-bandgap output (close to but slightly shorter than the ~1.1 μm edge)

Main reason it is difficult under sunlight

Nonlinearity + low irradiance: UC probability is very low at 1 sun, so gains are hard to realize

Often limited by weak/narrow absorption entrance; device optical losses can substantially erode material-side benefits

Typical systems (examples)

Yb³/Er³⁺, Yb³/Tm³⁺ (ETU/ESA, etc.)

Tb³  2Yb³⁺ cooperative energy transfer; Pr³⁺  Yb³⁺ two-step energy transfer, etc.

Host/material engineering focus

Low-phonon-energy hosts (β-NaYF, etc.); coreshell structures to suppress surface quenching and OH

Low-phonon/low-defect hosts + optimization of dopant ratios and energy-migration pathways to avoid migration to defect sinks

Placement intuition

Typically on the rear side of the cell, with a back reflector to return emission into the cell

Typically on the front side to process high-energy photons; requires high transparency, low parasitic absorption, and reduced emission escape

Representative “high-intensity demonstration” data (condition-sensitive)

Example: relatively high device EQE reported under 1523 nm, 2.4 W/cm² monochromatic pumping (not directly achievable at 1 sun)

IQY >100% at the material level does not guarantee device gain; absorption and optical coupling must deliver photons into the cell

Downconversion / Quantum Cutting: Why It Is More “Matched” to Silicon

1. Core concept: splitting one high-energy photon into two near-bandgap photons

  • For crystalline silicon (c-Si), high-energy photons (shorter wavelengths) can be absorbed, but the excess energy above the bandgap is largely lost as heat through carrier thermalization. By contrast, longer-wavelength photons beyond ~1100 nm are difficult for silicon to absorb. The concept of quantum cutting is to split the energy of one high-energy photon into two lower-energy photons that are closer to the bandgap. From the standpoint of reducing thermalization loss, this approach is conceptually better aligned with silicon solar cells.

2. Why Yb³ is often used as the terminal acceptor

  • Yb³ has a very simple energy-level structure. Its dominant emission arises from the ²F/  ²F/ transition, with an energy gap of about 10,000–10,200 cm⁻¹, corresponding to ~980–1000 nm (often extending toward ~1030 nm depending on the host). This makes Yb³ an excellent energy-packaging endpoint”: as long as the donor provides slightly more than roughly 2×E(Yb) and the energy can be distributed efficiently, a single absorption event can, in principle, be “split” into two NIR emissions. Theoretically, the material-side internal quantum yield can approach ~200%.

Quantum-Cutting Routes and Practical Bottlenecks

Typical donor → acceptor routes (example table)

Route (donor → acceptor)

Main mechanism

Absorption entrance (examples)

Main output

Meaning for silicon (intuitive explanation)

Tb³  2Yb³⁺

Cooperative energy transfer (the donor transfers energy to two acceptors simultaneously)

UV/visible (depending on donor absorption/sensitization)

Two ~1 μm NIR photons (Yb³)

Increases the number of near-bandgap photons, mechanistically counteracting thermalization loss

Pr³  Yb³⁺ (×2)

Two-step energy transfer (the donor sequentially distributes energy to two Yb³ ions)

Visible/UV (system-dependent)

~1 μm (Yb³)

Same as above; a common route that is convenient for screening and benchmarking

Summary: The primary criterion for route selection is whether the donor can efficiently and reproducibly partition the energy from a single absorbed photon into two portions, and—via energy transfer—inject them separately into the ~1 μm emission channel of Yb³, while suppressing non-radiative dissipation and competing pathways as much as possible.

Key Hurdles from “Material IQY > 100%” to “Device-Level Gain”

Hurdle

Why it becomes limiting

How to verify (recommended controls)

Common improvement approaches

 Weak/narrow absorption entrance

Many systems are still limited by narrow absorption; broadband sunlight cannot be harvested efficiently

Always report absorption spectrum/absorptance; compare device-side changes at the same layer thickness

Sensitization/broadband antenna absorbers; introduce allowed-transition absorption channels

 Concentration quenching / defect dissipation

Higher doping is often required to boost transfer, but energy migration is easily trapped by defects

Doping-dependence studies (intensity/lifetime/QY vs dopant concentration)

Optimize dopant ratios; improve crystal quality; core–shell/isolation structures

 Emission escape and poor optical coupling

Emitted NIR photons are not guaranteed to enter and be absorbed by the cell; interface reflection/scattering causes escape

Modify index matching/thickness/reflectors and check whether device-side improvement follows consistently

Refractive-index matching; AR/reflective structures; thickness and optical-path engineering

 Reliability / packaging compatibility (recommended)

Front-side layers must withstand UV, damp heat, and thermal cycling; some sensitizers may be unstable

Compare spectra/QY/device response before and after accelerated aging

Use stable inorganic systems; moisture/oxygen barrier encapsulation; avoid structures with high parasitic absorption

Summary: The key to QC is not only maximizing the material IQY, but also simultaneously achieving: sufficient absorptance under sunlight, minimal non-radiative loss along the energy-transfer chain, effective coupling of the emitted photons into the cell (and absorption by the cell), and long-term stability and packaging compatibility.


Experimental Checklist for Upconversion vs Quantum Cutting: Key Tests, Mandatory Conditions, and Decision Criteria

Item

Upconversion (UC)

Downconversion / Quantum Cutting (DC/QC)

Loss you aim to compensate

Sub-bandgap transmission (low-energy photons would otherwise not be absorbed)

High-energy thermalization (excess energy far above Eg is lost as heat)

Typical target cells

c-Si, thin-film Si, etc. (focus on transmitted NIR)

c-Si, etc. (split UV/visible into photons closer to Eg; ~1000 nm is a common target)

Recommended placement

Typically on the rear side of the cell (using transmitted sub-bandgap light), with a back reflector to return emission

Typically on the front side (processing high-energy photons); requires high transparency and low parasitic absorption

Most sensitive aspect of light-source conditions

Extremely dependent on power density (nonlinear: efficiency drops sharply at low intensity)

Less sensitive than UC (closer to linear), but still strongly dependent on absorptance, transfer efficiency, and non-radiative losses

Typical material systems

Yb³/Er³⁺, Yb³⁺/Tm³⁺; hosts often include low-phonon fluorides such as β-NaYF

Tb³  2Yb³⁺ cooperative transfer; Pr³⁺–Yb³⁺ two-step transfer; Yb³⁺ often used as the acceptor (~1000 nm emission)

Must-measure “material-side” metrics

Emission spectra; lifetimes; power dependence (slope/saturation); temperature dependence; report UCQY (or equivalent QY definition) with conditions

Absorption spectra (solar-harvesting capability); emission spectra (~1000 nm); IQY (>100%? preferably integrating-sphere/absolute methods to avoid geometry/reabsorption artifacts); concentration dependence and quenching evidence

Must-report experimental conditions

Excitation wavelength/bandwidth; power density (ideally spot size and calibration); sample thickness and geometry; presence/absence of back reflector/cavity

Incident spectrum (broadband or monochromatic); sample absorptance/thickness; IQY/EQY definitions; whether reabsorption/scattering exists; interface reflection and index-matching strategy

Most common “looks effective but yields no gain” pitfalls

Bright under high-power laser, but nearly no response at 1 sun; optical enhancement introduces parasitic absorption/heating that can harm the cell

IQY >100% but isotropic emission + interface reflection means most photons never enter the cell; high doping drives migration to defect sinks

Quick criteria suggesting real efficiency improvement

Under near-1-sun effective power density, material QY remains meaningful and repeatable increases in device EQE/current are measurable

Demonstrate that emitted NIR actually enters and is absorbed by the cell: e.g., device EQE/current increases track optical-structure changes consistently, rather than only showing high material IQY

Core Materials and Product List (Aladdin)

This list highlights three categories of key materials: lanthanide precursors and dopant sources for energy-transfer engineering (Ln salts/fluorides), low-phonon-energy fluoride hosts and key components for ZBLAN fluoride glass (to increase radiative transition probability and suppress multiphonon relaxation), and representative oxide host materials suitable for device-integration routes such as coatings, thin films, and ceramics.

Category

CAS No.

Aladdin Cat. No.

Product name

Grade/Purity

Role / key features

Rare-earth nitrate precursor (sensitization/doping)

10294-41-4

C431281

Cerium(III) nitrate hexahydrate

Ultra pure grade

Ce³ solution-route precursor: used to introduce a broadband absorption entrance for sensitization or doping synthesis

Rare-earth nitrate precursor (sensitization/doping)

10294-41-4

C105376

Cerium nitrate hexahydrate

≥99.5% metals basis

Same; commonly used in sol–gel, co-precipitation, and solution-doping routes

Rare-earth nitrate precursor (sensitization/doping)

10294-41-4

C105378

Cerium nitrate hexahydrate

≥99.95% metals basis

Same; higher purity helps reduce impurity-related quenching risk

Rare-earth nitrate precursor (sensitization/doping)

10294-41-4

C431280

Cerium(III) nitrate hexahydrate

PrimorTrace™, ≥99.999% metals basis

Same; suitable for demanding optical/luminescence mechanism studies

Rare-earth nitrate precursor (sensitization/doping)

10294-41-4

C431279

Cerium(III) nitrate hexahydrate

≥99% metals basis

Same

Rare-earth fluoride precursor (host/component)

13709-49-4

Y106114

Yttrium fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis, powder

Typical fluoride host/component (e.g., YF-based systems) for RE-doped luminescence and energy-transfer materials

Rare-earth fluoride precursor (host/component)

13709-49-4

Y106115

Yttrium fluoride

Anhydrous, ≥99.9% metals basis

Same

Rare-earth fluoride precursor (energy-transfer chain/component)

13765-26-9

G119154

Gadolinium(III) fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis, powder

Component for Gd³-related energy-transfer chains; used in luminescent-material system design

Rare-earth fluoride precursor (energy-transfer chain/component)

13765-26-9

G140159

Gadolinium(III) fluoride

Anhydrous, ≥99.9% metals basis, powder

Same

Rare-earth fluoride precursor (candidate donor)

13709-42-7

N113328

Neodymium fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis

Nd³ as a level-matching candidate donor (e.g., NdYb) for spectral-conversion screening

Rare-earth fluoride precursor (candidate donor)

13709-42-7

N122097

Neodymium fluoride

Anhydrous, ≥99.9% metals basis

Same

Rare-earth fluoride precursor (candidate donor)

13760-78-6

H119102

Holmium(III) fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis, powder

Ho³ as a level-matching candidate donor (HoYb, etc.) for exploratory studies

Rare-earth fluoride precursor (candidate donor)

13760-78-6

H1419778

Holmium(III) fluoride

Anhydrous, ≥99.9% metals basis, powder

Same

Rare-earth fluoride precursor (enhanced absorption / sensitization entrance)

7758-88-5

C105384

Cerium fluoride

≥99.9% metals basis

Ce³-related approach for a stronger absorption entrance/sensitization (more favorable than ff absorption)

Rare-earth fluoride precursor (enhanced absorption / sensitization entrance)

7758-88-5

C105383

Cerium fluoride

PrimorTrace™, ≥99.99% metals basis

Same; higher purity helps suppress impurity absorption and quenching

Rare-earth fluoride precursor (UC activator)

13760-83-3

E118852

Erbium fluoride

Anhydrous, ≥99.9% metals basis

Er³ classic UC activator (often paired with Yb³⁺)

Rare-earth fluoride precursor (UC activator)

13760-83-3

E684644

Erbium fluoride

≥99.5%

Same

Rare-earth fluoride precursor (UC activator)

13760-83-3

E106116

Erbium fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis

Same; for high-requirement luminescence/UC systems

Rare-earth fluoride precursor (DC donor / luminescent system)

13765-25-8

E123599

Europium(III) fluoride

Anhydrous, ≥99.5% metals basis

Eu³ often used as an emitter/acceptor in energy-transfer-chain systems

Rare-earth fluoride precursor (DC donor / luminescent system)

13765-25-8

E119159

Europium(III) fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis

Same

Rare-earth fluoride precursor (UC activator)

13760-79-7

T119081

Thulium(III) fluoride, anhydrous

PrimorTrace™, ≥99.99% metals basis, powder, anhydrous

Tm³ classic UC activator (often paired with Yb³⁺) for extended emission design

Rare-earth fluoride precursor (QC donor)

13708-63-9

T171307

Terbium(III) fluoride

Anhydrous, ≥99.995% metals basis

Tb³ classic QC donor; enables cooperative transfer to 2×Yb³⁺

Rare-earth fluoride precursor (QC donor)

13708-63-9

T171306

Terbium(III) fluoride

PrimorTrace™, ≥99.99% metals basis

Same

Rare-earth fluoride precursor (QC donor)

13708-63-9

T119247

Terbium(III) fluoride

Anhydrous, ≥99.9% metals basis, powder

Same

Rare-earth fluoride precursor (QC donor)

13709-46-1

P119204

Praseodymium(III) fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis, powder

Pr³ typical QC donor (PrYb two-step transfer approach)

Rare-earth fluoride precursor (UC sensitizer / DC acceptor)

13760-80-0

Y123600

Ytterbium fluoride

Anhydrous, ≥99.9% metals basis

Yb³: UC sensitizer / DC terminal acceptor and ~1000 nm emission center (matched to c-Si)

Rare-earth fluoride precursor (UC sensitizer / DC acceptor)

13760-80-0

Y111793

Ytterbium fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis

Same; higher purity helps reduce quenching and parasitic absorption

Rare-earth fluoride precursor (UC sensitizer / DC acceptor)

13760-80-0

Y432011

Ytterbium(III) fluoride

Granular, ≤1.6 mm

Same; granular form is convenient for solid-state and melt-processing feed

Rare-earth fluoride precursor (UC sensitizer / DC acceptor)

13760-80-0

Y140959

Ytterbium fluoride dihydrate

PrimorTrace™, ≥99.99% metals basis

Suitable for some solution/complexation routes (manage water content carefully)

Fluoride glass/ZBLAN component (transparent, low phonon energy)

7783-64-4

Z615368

Zirconium fluoride

≥99% metals basis

One of the main components of ZBLAN glass (ZrF); key for transparent, low-phonon-energy matrices

Fluoride glass/ZBLAN component (transparent, low phonon energy)

7783-64-4

Z196202

Zirconium fluoride

≥99.9% metals basis

Same; more suitable for optical/luminescence systems

Fluoride glass/ZBLAN component (transparent, low phonon energy)

7787-32-8

B104295

Barium fluoride

≥99%

Key component in ZBLAN-type fluoride glasses; low phonon energy and good IR transmission

Fluoride glass/ZBLAN component (transparent, low phonon energy)

7787-32-8

B104294

Barium fluoride

≥99.9% metals basis

Same

Fluoride glass/ZBLAN component (transparent, low phonon energy)

7787-32-8

B434108

Barium fluoride

PrimorTrace™, ultra pure grade, ≥99.99% metals basis

Same; optical-grade preferred

Fluoride glass/ZBLAN component (transparent, low phonon energy)

7787-32-8

B104296

Barium fluoride

PrimorTrace™, ≥99.99% metals basis

Same

Fluoride glass/ZBLAN component (transparent, low phonon energy)

13709-38-1

L171310

Lanthanum fluoride

PrimorTrace™, ≥99.99% metals basis, 1–5 mm

One of the key ZBLAN components; also a reference host/component for RE fluoride systems

Fluoride glass/ZBLAN component (transparent, low phonon energy)

13709-38-1

L102204

Lanthanum fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis

Same

Fluoride glass/ZBLAN component (transparent, low phonon energy)

7784-18-1

A118462

Aluminum fluoride

Anhydrous, ≥99%

Key ZBLAN component; improves glass-network stability

Fluoride glass/ZBLAN component (transparent, low phonon energy)

7784-18-1

A105069

Aluminum fluoride

Anhydrous, ≥99.9% metals basis

Same

Fluoride glass / fluorine-source component (core)

7681-49-4

S433801

Sodium fluoride

PrimorTrace™, anhydrous, ≥99.99% metals basis, powder

Key component for ZBLAN/fluoride systems; anhydrous high purity supports better process control

Low-phonon-energy fluoride material/matrix (core)

7789-75-5

C104253

Calcium fluoride

PrimorTrace™, ≥99.99% metals basis

CaF: classic low-phonon, highly transparent fluoride for matrices/windows/composites

Barium-source precursor (glass/transparent-layer routes)

513-77-9

B139811

Barium carbonate

PrimorTrace™, ≥99.99% metals basis

BaCO: barium source precursor commonly used in glass/optical formulations (paired with fluoride routes)

Oxide host (coating/thin-film/ceramic routes)

1314-36-9

Y103890

Yttrium oxide

≥99.9% metals basis

Common oxide host (stable; film/ceramic compatible) but with higher phonon energy than fluorides

Oxide host (coating/thin-film/ceramic routes)

1314-36-9

Y103888

Yttrium oxide

PrimorTrace™, ≥99.999% metals basis

Same; higher purity benefits optical/luminescent performance

Oxide host (coating/thin-film/ceramic routes)

1314-36-9

Y103885

Yttrium oxide

PrimorTrace™, ≥99.99% metals basis

Same

Oxide host (coating/thin-film/ceramic routes)

1314-36-9

Y431838

Yttrium oxide 99+

For analysis, AR grade, ≥99%

Same; convenient for general R&D

Oxide host (sputtering target)

1314-36-9

Y431837

Yttrium(III) oxide

≥99.99% metals basis, sputtering target, diam. × thickness 2.00 in. × 0.25 in.

Sputtering target for YO thin films/functional layers (optical coupling/protective-layer routes)

Supporting / Optional Product List

This section mainly covers solvents/surface ligands/fluorine sources for RE fluoride nanocrystal synthesis, plus gold/silver precursors and stabilization systems for plasmonic enhancement (Au/Ag precursors, citrate, etc.), and a small number of semiconductor reference materials for device testing (e.g., Si, GaAs).

Only representative catalog numbers are listed here. For additional grades and specifications, please search the Aladdin website by CAS number or refer to the consolidated product list at the end of this article.

Category

CAS No.

Aladdin Cat. No.

Product name

Grade/Purity

Role / key features

Organic solvent / surface ligand (nanocrystal synthesis)

112-88-9

O109488

1-Octadecene

Analytical standard, ≥99.5% (GC)

High-boiling solvent commonly used for UC/RE fluoride nanocrystal synthesis (thermal decomposition/solvothermal)

Organic ligand (NaREF nanocrystal synthesis)

112-80-1

O108485

Oleic acid

Moligand™, ≥99% (HPLC)

Common surface ligand/capping agent affecting size, morphology, and surface quenching

Organic ligand (NaREF nanocrystal synthesis)

112-90-3

O106967

Oleylamine

C18: 80–90%

Coordinating solvent/surface ligand to tune crystal growth and surface states

Fluorine source / precursor additive (fluoride formation)

2923-18-4

S665022

Sodium trifluoroacetate

≥99%

Common in trifluoroacetate routes for RE fluoride nanocrystals/powders (process support)

Stabilizer / complexing agent (metal nanoparticles/colloids)

6132-04-3

S116314

Sodium citrate dihydrate

ACS, ≥99% (NT)

Common complexing/stabilizing reagent for Au/Ag nanoparticles (plasmonic routes)

Stabilizer / complexing agent (metal nanoparticles/colloids)

6132-04-3

S425079

Sodium citrate dihydrate

10 mM in Water

Ready-to-use solution for rapid screening and reproducibility control in Au/Ag nanoparticle synthesis

Noble-metal precursor (plasmonic enhancement)

16961-25-4

G141105

Chloroauric acid trihydrate (HAuCl₄·3HO)

≥99.9% metals basis

Au precursor for gold nanostructures (optical coupling studies for UC excitation/emission)

Silver precursor (plasmonic enhancement)

7761-88-8

S116265

Silver nitrate (regulated precursor)

PrimorTrace™, ≥99.99% metals basis

Ag precursor for silver nanostructures (ensure regulatory compliance and proper storage/handling)

Fluoride-system support (solution)

7681-49-4

S433803

Sodium fluoride solution

0.5 M in HO

Convenient for preparing F-containing solutions (more for solution tests than anhydrous solid synthesis)

Semiconductor reference (device testing)

7440-21-3

S434708

Silicon

Plate, 40×40 mm, thickness 3.0 mm, single crystal, p-type, 100

Reference material for cell/device testing (not a spectral-conversion material itself)

Semiconductor material (device example)

1303-00-0

G119227

Gallium arsenide

PrimorTrace™, ≥99.999% metals basis, pieces

Used in spectral-conversion/UC device demonstrations or comparative studies (not the core spectral-conversion layer material)

 

Aladdin: https://www.aladdinsci.com/

Categories: Technical articles
Explore topics: Quantum Cutting

Da — when not otherwise indicated, molecular weight units are daltons.   Mw — weight-average molecular weight.   Mn — number-average molecular weight.

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Cite this article

Aladdin Scientific. "From Spectral Mismatch to Device Gain: Key Mechanisms, Experimental Guidance, and Aladdin Material Selection for Lanthanide Upconversion and Downconversion (Quantum Cutting) in Solar Cells" Aladdin Knowledge Base, updated 22 dic 2025. https://www.aladdinsci.com/us_es/faqs/from-spectral-mismatch-to-device-gain-en.html
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