REVIEW 3 major objections 4 minor 2 references
Diamine Surface Passivation and Post-Annealing Enhance Performance of Silicon-Perovskite Tandem Solar Cells
T0 review · 3 major / 4 minor · reviewed 2026-08-12 · deepseek-v4-flash
Pith's one-line read Treating a wide-bandgap perovskite with 1,3-diaminopropane and then annealing the C60 layer for one minute lifts silicon-perovskite tandem efficiency from 23.26% to 25.29%.
desk verdict Real single-junction gains and nice surface chemistry, but the tandem claim needs a control+anneal arm before it fully holds. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The mechanism is a surface chemical conversion plus a thermal reflow. DAP (1,3-diaminopropane) deposited from a 0.75 mM isopropanol solution reacts with formamidinium (FA+) at the perovskite surface to form the six-membered ring cation 1,4,5,6-tetrahydropyrimidinium (THP+), eliminating ammonia; ToF-SIMS profiles show THP+ concentrated in the first ~70 nm. The one-minute, 150 °C anneal after C60/BCP evaporation then acts on the whole stack: hyperspectral photoluminescence from the bottom interface shows the PL peak blueshifting from ~742 nm to ~733 nm, which the authors interpret as a more homogeneous bromide/iodide distribution that prevents bandgap pinning, while PL maps from the top show fewer unquenched bright spots, indicating fuller pinhole-free C60 coverage. These two observations carry the argument that VOC gains come from chemical passivation and FF gains come from the anneal's homogenization and improved contact.
What would settle it
Fabricate a batch of at least ten silicon-perovskite tandems per condition (control, DAP only, DAP + anneal) from the same wafer and process runs, and compare the mean and standard deviation of PCE, VOC, and FF; if the DAP + anneal mean does not exceed the control mean by a statistically significant margin, the claimed 2 percentage-point gain fails. As a mechanistic check, measure the bottom-interface PL peak position on every annealed device to confirm the blueshift appears consistently and correlates with higher FF.
Extended reading notes
Core claim
The central claim is that chemical reactivity at the perovskite surface, rather than simply the presence of a Lewis-base layer, is what makes DAP passivation effective. DAP reacts with FA+ cations near the surface to form 1,4,5,6-tetrahydropyrimidinium (THP+), a larger molecular cation that remains in the top ~70 nm of the film and passivates surface defects, raising VOC from 1.06 V to 1.15 V in single junctions. The subsequent one-minute anneal after C60/BCP deposition shifts the bottom-interface photoluminescence peak toward shorter wavelengths, indicating a more homogeneous wide-bandgap composition and better C60 adhesion, which the authors link to a fill-factor increase of about 20% relative to control. The authors show the combination transfers to 1 cm2 silicon-perovskite tandems, where the champion PCE rises from 23.26% to 25.29%.
Load-bearing premise
The central claim depends on the champion tandem efficiencies (23.26% control vs 25.29% treated) being representative of a systematic processing improvement rather than run-to-run device variation, because the paper reports only champion values for the tandems.
Editorial extensions
If this is right
- In 1.7 eV single-junction cells, the DAP + anneal treatment lifts champion PCE from 15.49% (control) to 19.11%, with VOC rising from 1.06 V to 1.15 V and fill factor from 63.4% to above 75%.
- In 1 cm2 silicon-perovskite tandems, the champion PCE rises from 23.26% (control) to 25.29%, with champion VOC of 1.915 V and FF of 0.70.
- Encapsulated devices that received the anneal, with or without DAP, retain PCE, VOC, and FF better over 324 hours of ISOS-L2 aging at 85 °C, while JSC is unchanged.
- The post-annealing step also boosts performance when other amines, lysine and polyallylamine, are used as interlayers, indicating the thermal step supports the fill-factor gain.
Reading between the lines
- The reaction is confined to the top ~70 nm of the film, so the same chemistry could tailor the A-site composition near interfaces of other perovskite stacks without altering the bulk bandgap, a design freedom the paper leaves unexplored.
- The anneal-induced blueshift at the bottom interface suggests thermal post-processing could also suppress halide segregation in other wide-bandgap compositions, including all-perovskite tandems, not just the silicon-based stack tested here.
- Because the tandem comparison uses champion cells, a next step would be to measure the mean and spread of PCE over multiple fabrication runs to quantify the average gain.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript reports that applying 1,3-diaminopropane (DAP) at the perovskite/C60 interface, followed by a short post-deposition anneal, improves the performance of 1.7 eV mixed-halide perovskite single junctions (champion PCE from 15.49% to 19.11%) and of Si-perovskite tandems (champion PCE from 23.26% to 25.29%). The authors combine hyperspectral PL imaging, ToF-SIMS, XRD/GIWAXS, and stability measurements to propose that DAP reacts with surface formamidinium to form THP+ and that annealing homogenizes the perovskite composition and improves C60 adhesion.
Significance. If the tandem gain is reproducible and attributable to the combined treatment, this is a practically relevant, low-cost processing addition. The mechanistic picture is supported by independent characterization: PL microscopy shows spatial homogenization after annealing; ToF-SIMS shows a DAP-derived species at the interface; stability data (ISOS L-2) show improved retention with annealing. The manuscript is generally well written and the single-junction statistics are provided in Table S1. However, the central tandem claim currently rests on a single champion device and lacks a crucial control arm, which limits the strength of the conclusion.
major comments (3)
- [Figure 4 and Table S2] The tandem matrix includes control, DAP, and DAP+anneal, but no control+anneal device. Since single-junction data (Figure S6) show that annealing alone improves performance, and since the DAP-only tandem is worse than control (PCE 22.72% vs 23.26%, FF 0.63 vs 0.65), the 25.29% champion could be dominated by the annealing step rather than by a DAP-anneal synergy. Please add a control+anneal tandem arm, or explicitly restrict the claim to 'DAP+anneal vs control' and discuss the confounding annealing effect.
- [Figure 1 vs Figure 4] The single-junction results show DAP improves PCE from 15.49% to 18.24% (Figure 1, Table S1), yet the DAP-only tandem shows lower PCE, VOC, FF, and Jsc than the control (Figure 4 and Figure S18). This inconsistency needs an explanation; without it, the reader cannot determine whether DAP is beneficial in the tandem stack or whether its apparent benefit in the champion DAP+anneal device arises from device-to-device variation.
- [Abstract, Table S2] Performance claims in the abstract and conclusion are based on champion values. Table S1 reports means and standard deviations for single junctions, but the tandem results in Table S2 are presented as averages without error bars or device counts. Please report the number of tandem devices and the mean ± SD (or box plots) for each arm, and state whether the 25.29% vs 23.26% difference is statistically significant.
minor comments (4)
- [Conclusion] The sentence 'the tail groups of the recently reported in recent amine-silane based passivation schemes' is grammatically incomplete and appears to have a missing reference; please revise.
- [Figure 3a] The reaction scheme labels the eliminated species as 'NH3+'; neutral ammonia is NH3, so the label should be corrected to avoid confusion with an ammonia radical cation.
- [Abstract and Results] The phrase 'improves the fill factor (FF) by 20%' should specify whether this is a relative or absolute improvement, since the numbers in Figure 1 (63.4% to over 75%) imply a relative increase of roughly 20% but an absolute increase of roughly 12 percentage points.
- [Reference 48] The author list for reference 48 contains 'null' as an author entry; this formatting error should be corrected.
Circularity Check
No significant circularity: the performance claims are new measurements, and the mechanistic analogy to prior amine–FA chemistry is external support, not a fitted input or self-referential derivation.
full rationale
This paper is an experimental study, not a modeling or derivation paper. The central claims, that DAP surface treatment and post-C60 annealing improve single-junction and tandem PCE, VOC, and FF, are direct measurements reported with J-V curves, statistics in Table S1, and device data in Figures 1 and 4. There is no fitted parameter that is later renamed as a prediction, no equation that defines the output in terms of the input, and no uniqueness theorem imported from prior work. The mechanistic interpretation that DAP reacts with FA+ to form THP+ is supported by ToF-SIMS data in Figure 3 and is presented as analogous to prior work on EDA and benzylamine reactivity (refs 10 and 44). That prior work is external, independently published evidence; it does not define the measured efficiency improvements, so it is not load-bearing in the sense of forcing the main result. The discussion of annealing improving compositional homogeneity is an interpretation of PL data, not a circular derivation. The absence of a control-plus-anneal tandem arm is an experimental-design limitation and a legitimate correctness concern, but it is not circularity: the DAP-plus-anneal tandem result is still a measured value, not a quantity deduced from assumptions that already contain it. Optimizing the DAP concentration on the same efficiency metric is standard experimental optimization, not a fitted input being called a prediction. Accordingly, no circular step can be exhibited with a quote that reduces a claimed result to its own inputs.
Assumptions & free parameters
free parameters (3)
- DAP concentration =
0.75 mM
- Annealing temperature =
150 °C
- Annealing time =
1 minute
assumptions (4)
- domain assumption ToF-SIMS m/z=85 peak corresponds to THP+ and indicates formation of the cyclic cation from DAP and FA.
- domain assumption Blueshift of PL peak wavelength after annealing indicates improved compositional homogeneity and better energy alignment, which explains the FF gain.
- domain assumption Fewer bright spots in PL maps correspond to better C60 coverage and fewer pinholes, directly influencing FF.
- domain assumption The solid-state reaction of DAP with surface FA is analogous to the solution reaction of EDA with FA reported previously by the same group.
Cite this review
Pith. "Pith review of Diamine Surface Passivation and Post-Annealing Enhance Performance of Silicon-Perovskite Tandem Solar Cells." pith.science (2026). https://pith.science/paper/ZMHOA4NE
@misc{pith2026241118756,
author = {Pith},
title = {Pith review of: Diamine Surface Passivation and Post-Annealing Enhance Performance of Silicon-Perovskite Tandem Solar Cells},
year = {2026},
howpublished = {\url{https://pith.science/paper/ZMHOA4NE}},
note = {Machine review of arXiv:2411.18756}
}
read the original abstract
We show that the use of 1,3-diaminopropane (DAP) as a chemical modifier at the perovskite/electron-transport layer (ETL) interface enhances the power conversion efficiency (PCE) of 1.7 eV bandgap FACs mixed-halide perovskite single-junction cells, primarily by boosting the open-circuit voltage (VOC) from 1.06 V to 1.15 V. Adding a post-processing annealing step after C60 evaporation, further improves the fill factor (FF) by 20% from the control to the DAP + post-annealing devices. Using hyperspectral photoluminescence microscopy, we demonstrate that annealing helps improve compositional homogeneity at the top and bottom interfaces of the solar cell, which prevents detrimental bandgap pinning in the devices and improves C60 adhesion. Using time-of-flight secondary ion mass spectrometry, we show that DAP reacts with formamidinium present near the surface of the perovskite lattice to form a larger molecular cation, 1,4,5,6-tetrahydropyrimidinium (THP) that remains at the interface. Combining the use of DAP and the annealing of C60 interface, we fabricate Si-perovskite tandems with PCE of 25.29%, compared to 23.26% for control devices. Our study underscores the critical role of chemical reactivity and thermal post-processing of the C60/Lewis-base passivator interface in minimizing device losses and advancing solar-cell performance of wide-bandgap mixed-cation mixed-halide perovskite for tandem application.
Reference graph
Works this paper leans on
-
[739]
https://doi.org/10.1021/acsenergylett.3c02701. (39) Perini, C. A. R.; Castro-Mendez, A.-F.; Kodalle, T.; Ravello, M.; Hidalgo, J.; Gomez- Dominguez, M.; Li, R.; Taddei, M.; Giridharagopal, R.; Pothoof, J.; Sutter-Fella, C. M.; Ginger, D. S.; Correa-Baena, J.-P. Vapor-Deposited n = 2 Ruddlesden–Popper Interface Layers Aid Charge Carrier Extraction in Perov...
-
[7454]
(21) Stolterfoht, M.; Wolff, C
https://doi.org/10.1038/s41467-022-34203-x. (21) Stolterfoht, M.; Wolff, C. M.; Márquez, J. A.; Zhang, S.; Hages, C. J.; Rothhardt, D.; Albrecht, S.; Burn, P. L.; Meredith, P.; Unold, T.; Neher, D. Visualization and Suppression of Interfacial Recombination for High-Efficiency Large-Area Pin Perovskite Solar Cells. Nat Energy 2018, 3 (10), 847–854. https:/...
Reviewed August 12, 2026 · model on record in the stance chip above.
Discussion (0). Continue with ORCID to comment.