Hydrazine-Free Precursor for Solution-Processed All-Inorganic Se and Se1-xTex Photovoltaics

Adam D. Alfieri; Cherie R. Kagan; Chloe Leblanc; Deep Jariwala; Eric A. Stach; Jamie Ford; Kim Kisslinger; Swarnendu Das

REVIEW 4 major objections 1 minor 2 references

Hydrazine-Free Precursor for Solution-Processed All-Inorganic Se and Se1-xTex Photovoltaics

T0 review · 4 major / 1 minor · reviewed 2026-08-05 · deepseek-v4-flash

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Pith's one-line read A thiol-amine solvent system replaces hydrazine for solution-processing Se and Se-Te photovoltaics, yielding bandgaps from 1.20 to 1.86 eV and efficiencies up to 2.73%.

desk verdict A plausible hydrazine-free Se/Se1-xTex PV advance, but the submitted full text is a DICOM paper, so the claims are unverifiable from this submission. read the letter →

arxiv 2508.07530 v1 pith:2ERMBGR6 submitted 2025-08-11 cond-mat.mtrl-sci

Adam D. Alfieri , Swarnendu Das , Kim Kisslinger , Chloe Leblanc , Jamie Ford , Cherie R. Kagan , Eric A. Stach , Deep Jariwala This is my paper · ORCID

classification cond-mat.mtrl-sci

keywords hydrazine-freeprocessingseleniumphotovoltaicsselenium-telluriumalloysmolecularinkpropylammoniumpoly-selenidebandgaptuningthiol-aminesolventsolution-processedsolarcells

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper proposes a hydrazine-free route to solution-processing selenium and selenium-tellurium alloy photovoltaics. The authors prepare a propylammonium poly-Se (and poly-Se-Te) precursor from a thiol-amine solvent, redissolve it in dimethylformamide with monoethanolamine to make a molecular ink, and deposit films with bandgaps between 1.20 and 1.86 eV. They report working solar cells with power conversion efficiencies up to 2.73% for Se and 2.33% for $\mathrm{Se}_{0.7}\mathrm{Te}_{0.3}$, using TiO$_2$ and MoO$_3$ transport layers, and no degradation of Se devices after one month in air. If these results hold, hydrazine, an extremely hazardous solvent previously required for this materials system, can be replaced by a safer solvent system without losing the bandgap tunability that makes Se-Te alloys attractive for indoor and tandem photovoltaics.

What carries the argument

The propylammonium poly-Se and poly-Se-Te precursor salts isolated from a thiol-amine solvent system. These are molecular species that dissolve into a DMF/EA ink; upon deposition and annealing they decompose to leave the desired chalcogenide film, and the Te fraction in the precursor is the bandgap knob.

What would settle it

Measure the Se:Te atomic ratio in annealed films by energy-dispersive X-ray spectroscopy or Rutherford backscattering across a series of inks with known Se:Te ratios; if the film composition does not track the ink composition, or if the films show phase segregation, the claimed composition-controlled bandgap tuning collapses. Independently, reproducing the device stack and finding no photovoltaic response above the noise floor would overturn the headline efficiency claim.

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Extended reading notes

Core claim

The central claim is that selenium and its tellurium alloys can be solution-processed into device-quality photovoltaic films without hydrazine. The authors say they synthesize propylammonium polychalcogenide precursors in a thiol-amine solvent, isolate them as solids, and dissolve them in DMF with a monoethanolamine additive to form stable molecular inks. From these inks they deposit Se and $\mathrm{Se}_{1-x}\mathrm{Te}_x$ films whose bandgap is set by the Te fraction, covering 1.20 to 1.86 eV. They then build PV devices with TiO$_2$ and MoO$_3$ charge-selective contacts and report maximum efficiencies of 2.73% for pure Se and 2.33% for $\mathrm{Se}_{0.7}\mathrm{Te}_{0.3}$, with Se cells sta

Load-bearing premise

The claim rests on the assumption that the Se:Te ratio in the molecular ink is faithfully carried through deposition and annealing into the final film, and that the reported 2.73% and 2.33% efficiencies and one-month stability come from well-defined, representative device measurements.

Editorial extensions

If this is right

If the process works as claimed, hydrazine can be retired from Se and Se-Te PV processing, removing a major safety and toxicity barrier to commercial solution manufacturing.
The demonstrated 1.20-1.86 eV bandgap range makes $\mathrm{Se}_{1-x}\mathrm{Te}_x$ a candidate absorber for tandem and indoor photovoltaics, where a tunable low-toxicity inorganic absorber is desirable.
Using inorganic TiO$_2$ and MoO$_3$ transport layers is a direct route to air-stable devices, consistent with the reported one-month stability of Se cells.
Because the precursor is isolated as a solid, inks can be formulated separately and potentially with other solvents and coating methods, broadening process compatibility.
The same molecular-precursor approach may extend to other chalcogenide alloys and photodetectors.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

The supplied full text is not the experimental portion of this paper; it is a different manuscript on DICOM medical-image de-identification. Therefore the abstract's claims about synthesis, film quality, bandgaps, and device metrics are not backed by experimental details in the provided text, and the reported efficiencies should be treated as unverified until the actual methods and statistics are
If the ink-to-film composition transfer is faithful, the bandgap-composition relation offers a controlled test: the paper implies a monotonic decrease from about 1.86 eV at x=0 to about 1.20 eV at the Te-rich end, which is directly measurable.
A natural extension the authors do not state: the same precursor chemistry could be tuned by varying the alkylammonium counterion (for example, ethyl versus butyl) to adjust solubility and film morphology.

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

The abstract describes a real step: isolating propylammonium poly-Se and poly-Se-Te precursors from a thiol-amine solvent, redissolving them in DMF/EA to make inks, and getting working Se and Se1-xTex devices with bandgaps from 1.2 to 1.9 eV and champion efficiencies of 2.73% and 2.33%. That is a sensible extension of known alkylammonium polychalcogenide chemistry, and if the composition retention claim holds, the continuous bandgap knob is genuinely useful for indoor PV and tandem work. Credit where due: the chemistry is plausible, the choice of inorganic CTLs is well-motivated, and the one-month air stability is a concrete, testable claim.

The problem is that the full text supplied with this arXiv submission is not this paper. It is a DICOM de-identification report from a different set of authors. So every experimental section, every figure, every table, and every reference list that would support the abstract is missing. That leaves the core claims as assertions: the ink's Se:Te ratio surviving dissolution and annealing, the bandgap values coming from proper Tauc analysis, the efficiencies coming from well-defined device areas and calibrated illumination, the stability test having a defined protocol. None of that can be checked from this submission. I'm not saying the work is wrong; I'm saying the manuscript is not here.

What can be said from the abstract alone: the novelty claim of being the first non-hydrazine solution route is plausible but unverified against prior art; the efficiency numbers are believable for an early-stage Se PV but without statistics they are just champions. These are standard soft spots for an experimental letter, not deep flaws. The full-text mismatch is the only hard problem, and it is a packaging or submission error, not a scientific one.

My take: if the actual manuscript exists, this deserves a serious referee. The chemistry is grounded in established precursor systems, the device results are testable, and the hydrazine-free angle matters to anyone working on solution-processed chalcogenides. As submitted, though, it should be sent back for the correct full text before any review. I would not cite it until I can see the experimental evidence.

Referee Report

4 major / 1 minor

Summary. The submission under arXiv:2508.07530 presents an abstract claiming a hydrazine-free solution route to Se and Se1-xTex photovoltaics: propylammonium poly-Se and poly-Se-Te precursors are prepared in a thiol-amine solvent system, redissolved in DMF with a monoethanolamine additive to form molecular inks, processed into films with bandgaps from 1.20 eV to 1.86 eV, and fabricated into PV devices reaching 2.73% (Se) and 2.33% (Se0.7Te0.3) power conversion efficiency, with Se devices stable for one month in air. However, the supplied full text is not this paper; it is arXiv:2508.07538, a DICOM image de-identification manuscript. No experimental sections, figures, tables, or data supporting any of the Se/Se1-xTex claims are present in the submitted manuscript.

Significance. If the abstract's claims were supported, this would be a significant materials-science advance: replacing hydrazine with a safer solvent system, demonstrating continuous bandgap tuning through Te alloying, and showing promising device stability with inorganic charge-transport layers. These are externally falsifiable, measured outcomes, so there is no circularity issue in principle. However, because the full text supplied is a different paper, the correctness, reproducibility, and statistical validity of the claims cannot be assessed. The paper as submitted contains only an abstract-level assertion with no evidentiary support.

major comments (4)

[Full text supplied (arXiv:2508.07538)] The body of this submission is a DICOM de-identification paper by Jiang et al., not the Se/Se1-xTex photovoltaic manuscript described in the abstract. None of the experimental methods, results, or figures for the claimed precursor synthesis, film processing, bandgap measurements, or device fabrication are present. This is a load-bearing omission: the central claims are empirical results that cannot be verified from the abstract alone.
[Abstract, bandgap claims] The abstract reports bandgaps from 1.20 eV to 1.86 eV for Se and Se1-xTex films. No optical absorption spectra, Tauc plots, compositional analyses (e.g., EDS/XRF), or XRD data are provided. The claim that the ink Se:Te ratio is preserved through deposition and annealing is essential for the continuous bandgap tuning; without compositional and structural evidence, this claim is unsubstantiated.
[Abstract, power conversion efficiency claims] The abstract reports champion PCEs of 2.73% for Se and 2.33% for Se0.7Te0.3. No J-V curves, device areas, active-area definitions, illumination calibration, device counts, or error bars are given. The phrase 'as high as' indicates champion values, and without statistics the reproducibility and representativeness of the reported efficiencies cannot be assessed.
[Abstract, stability claim] The abstract claims 'no degradation after 1 month in air' for Se devices. No stability data, storage conditions (humidity, temperature, illumination), or encapsulation details are supplied. This claim is not verifiable from the submitted manuscript.

minor comments (1)

[Submission metadata] The arXiv identifier 2508.07530 should correspond to the Se/Se1-xTex manuscript, but the supplied PDF is arXiv:2508.07538. The correct full text needs to be attached for review.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity identified: claims are direct experimental measurements; full-text mismatch is a verifiability issue, not circularity.

full rationale

The supplied abstract reports measured outcomes—precursor isolation, film bandgaps (1.20–1.86 eV), champion PCEs (2.73% for Se, 2.33% for Se0.7Te0.3), and one-month air stability—that are outputs of synthesis, optical characterization, and device testing against external benchmarks (solar simulation, absorption spectroscopy). There is no derivation chain, no fitted parameter renamed as a prediction, and no self-citation invoked to justify a central claim. The full text supplied with arXiv:2508.07530 is actually arXiv:2508.07538, a DICOM de-identification paper, so the experimental methods and data supporting the Se/Se1-xTex claims are absent from this submission. Per the review rules, missing support and unverifiability are correctness/evidentiary concerns, not circularity. No quoted equation or construction shows a claimed result reducing to its own input. A low circularity score is therefore appropriate; the mismatch is flagged here for completeness but does not constitute a circular-step finding.

Assumptions & free parameters 0 free parameters · 2 assumptions · 0 invented entities

This is an experimental materials paper; the only new things are chemical precursors (propylammonium poly-Se/poly-Se-Te), which are synthesized compounds rather than postulated entities in the physics sense, so no invented entities are listed. No free parameters are visible at the abstract level: all reported numbers are measurements, not fits. The main unstated support is the reliability of the processing and measurement methods, captured in the two domain assumptions.

assumptions (2)

domain assumption Standard photovoltaic characterization (J-V under simulated solar illumination, absorption-based bandgap extraction) yields accurate material and device parameters.
The abstract reports PCE and bandgap values without specifying measurement methodology; the validity of the headline numbers rests on standard, correctly executed characterization.
domain assumption The TiO2 and MoO3 charge transport layers form functional, non-reactive contacts, so the measured photocurrent originates from the Se/Se1-xTex absorber.
Device operation is attributed to the absorber; if the transport-layer interfaces dominate or react with the film, the efficiency claims would not reflect absorber quality.

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Cite this review

Pith. "Pith review of Hydrazine-Free Precursor for Solution-Processed All-Inorganic Se and Se1-xTex Photovoltaics." pith.science (2026). https://pith.science/paper/2ERMBGR6

@misc{pith2026250807530,
  author       = {Pith},
  title        = {Pith review of: Hydrazine-Free Precursor for Solution-Processed All-Inorganic Se and Se1-xTex Photovoltaics},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/2ERMBGR6}},
  note         = {Machine review of arXiv:2508.07530}
}

read the original abstract

Selenium (Se) has reemerged as a promising absorber material for indoor and tandem photovoltaics (PVs), and its alloys with Te (Se1-xTex) offer a widely tunable bandgap. Solution processing of this materials system offers a route to low-cost fabrication. However, solution processing of Se has, thus far, only used hydrazine, which is an extremely hazardous solvent. In this work, we prepare and isolate propylammonium poly-Se and poly-Se-Te precursors from a safer thiol-amine solvent system. We formulate molecular inks by dissolving the precursor n,n-dimethylformamide (DMF) with a monoethanolamine (EA) additive and process high-quality Se and Se1-xTex films with bandgaps ranging from 1.20 eV to 1.86 eV. We fabricate PVs from these films using TiO2 and MoO3 charge transport layers (CTLs) to achieve power conversion efficiencies as high as 2.73% for Se and 2.33% for Se0.7Te0.3 under solar simulation. Se devices show excellent stability with no degradation after 1 month in air, enabled by the excellent stability of Se and the use of inorganic CTLs. This work represents an important step towards low-cost solution-phase processing of Se and Se1-xTex alloys for PVs and photodetectors with low toxicity and high bandgap tunability.

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

2 extracted references · 2 canonical work pages

[1]

Introduction 1.1 MIDI-B De-identification In the era of digital healthcare, the processing and analy- sis of medical images are critical for diagnostics, treatment planning, and research (Aggarwal et al., 2021). One of the key challenges in this domain is the de-identification of medical images (Chevrier et al., 2019; Moore et al., 2012), which involves r...

work page 2021
[2017]

and Health Insurance Portability and Accountability Act (HIPAA) (Annas, 2003), and for promoting the respon- sible sharing of medical data. Medical images, particularly in the widely used Dig- ital Imaging and Communications in Medicine (DICOM) format (Bidgood et al., 1992), contain not only the image data but also sensitive metadata, such as patient name...

work page 2003

Pith tools

Reviewed August 5, 2026 · model on record in the stance chip above.

[1] [1]

Introduction 1.1 MIDI-B De-identification In the era of digital healthcare, the processing and analy- sis of medical images are critical for diagnostics, treatment planning, and research (Aggarwal et al., 2021). One of the key challenges in this domain is the de-identification of medical images (Chevrier et al., 2019; Moore et al., 2012), which involves r...

work page 2021

[2] [2017]

and Health Insurance Portability and Accountability Act (HIPAA) (Annas, 2003), and for promoting the respon- sible sharing of medical data. Medical images, particularly in the widely used Dig- ital Imaging and Communications in Medicine (DICOM) format (Bidgood et al., 1992), contain not only the image data but also sensitive metadata, such as patient name...

work page 2003