Energy Band Alignment by Solution-Processed Aluminum Doping Strategy toward Record Efficiency in Pulsed Laser-Deposited Kesterite Thin-Film Solar Cell.

Kesterite-based Cu2ZnSnS4 (CZTS) thin-film photovoltaics involve a serious interfacial dilemma, leading to severe recombination of carriers and insufficient band alignment at the CZTS/CdS heterojunction. Herein, an interface modification scheme by aluminum doping is introduced for CZTS/CdS via a spin coating method combined with heat treatment. The thermal annealing of the kesterite/CdS junction drives the migration of doped Al from CdS to the absorber, achieving an effective ion substitution and interface passivation. This condition greatly reduces interface recombination and improves device fill factor and current density. The JSC and FF of the champion device increased from 18.01 to 22.33 mA cm-2 and 60.24 to 64.06%, respectively, owing to the optimized band alignment and remarkably enhanced charge carrier generation, separation, and transport. Consequently, a photoelectric conversion efficiency (PCE) of 8.65% was achieved, representing the highest efficiency in CZTS thin-film solar cells fabricated by pulsed laser deposition (PLD) to date. This work proposed a facile strategy for interfacial engineering treatment, opening a valuable avenue to overcome the efficiency bottleneck of CZTS thin-film solar cells.

[1]  Z. Zheng,et al.  Over 10% Efficient Cu2CdSnS4 Solar Cells Fabricated from Optimized Sulfurization , 2022, Advanced Functional Materials.

[2]  T. Sham,et al.  Favorable Bonding and Band Structures of Cu2ZnSnS4 and CdS Films and Their Photovoltaic Interfaces. , 2022, ACS applied materials & interfaces.

[3]  Honglie Shen,et al.  Effect of CZTS/CCZTS Stacked Structures Prepared through Split-Cycle on the Performance of Flexible Solar Cells , 2022, ACS Applied Energy Materials.

[4]  Jiang Tang,et al.  Heterojunction Annealing Enabling Record Open‐Circuit Voltage in Antimony Triselenide Solar Cells , 2022, Advanced materials.

[5]  Xianghua Zhang,et al.  Crystal Growth Promotion and Defects Healing Enable Minimum Open‐Circuit Voltage Deficit in Antimony Selenide Solar Cells , 2022, Advanced science.

[6]  P. Fan,et al.  Pulsed laser deposited and sulfurized Cu2ZnSnS4 thin film for efficient solar cell , 2021, Solar Energy Materials and Solar Cells.

[7]  Yanhong Luo,et al.  Two-Step Annealing CZTSSe/CdS Heterojunction to Improve Interface Properties of Kesterite Solar Cells. , 2021, ACS applied materials & interfaces.

[8]  X. Hao,et al.  High-efficiency ultra-thin Cu2ZnSnS4 solar cells by double-pressure sputtering with spark plasma sintered quaternary target , 2021 .

[9]  Yiwei Yin,et al.  Revealing composition and structure dependent deep-level defect in antimony trisulfide photovoltaics , 2021, Nature Communications.

[10]  D. Ginger,et al.  Ag Incorporation with Controlled Grain Growth Enables 12.5% Efficient Kesterite Solar Cell with Open Circuit Voltage Reached 64.2% Shockley–Queisser Limit , 2021, Advanced Functional Materials.

[11]  M. Green,et al.  Kesterite Solar Cells: Insights into Current Strategies and Challenges , 2021, Advanced science.

[12]  Chengyan Liu,et al.  Band Edge Engineering for the Improvement of Open‐Circuit Voltage: Ag‐Based Selenized Cu 2 ZnSn(SSe) 4 Surface Regulated by Lithium , 2021 .

[13]  S. Liu,et al.  Defect Engineering in Earth‐Abundant Cu2ZnSn(S,Se)4 Photovoltaic Materials via Ga3+‐Doping for over 12% Efficient Solar Cells , 2021, Advanced Functional Materials.

[14]  J. H. Kim,et al.  A Facile Process for Partial Ag Substitution in Kesterite Cu2ZnSn(S,Se)4 Solar Cells Enabling a Device Efficiency of over 12. , 2021, ACS applied materials & interfaces.

[15]  M. Green,et al.  Defect Control for 12.5% Efficiency Cu2ZnSnSe4 Kesterite Thin‐Film Solar Cells by Engineering of Local Chemical Environment , 2020, Advanced materials.

[16]  L. Wong,et al.  Silver and Potassium Incorporation in Double-Layer Solution-Processed Cu2ZnSnS4 Solar Cell , 2020 .

[17]  J. Schou,et al.  Oxide route for production of Cu2ZnSnS4 solar cells by pulsed laser deposition , 2020 .

[18]  M. Green,et al.  Hydrothermal deposition of antimony selenosulfide thin films enables solar cells with 10% efficiency , 2020, Nature Energy.

[19]  Hong-li Ma,et al.  Sputtered and selenized Sb2Se3 thin-film solar cells with open-circuit voltage exceeding 500 mV , 2020 .

[20]  B. Yao,et al.  Enhancing the Performance of Aqueous Solution-Processed Cu2ZnSn(S,Se)4 Photovoltaic Materials by Mn2+ Substitution , 2020, Nanomaterials.

[21]  H. Hillhouse,et al.  Solution-based synthesis of kesterite thin film semiconductors , 2020, Journal of Physics: Energy.

[22]  T. Unold,et al.  Suppressed Deep Traps and Bandgap Fluctuations in Cu2CdSnS4 Solar Cells with ≈8% Efficiency , 2019, Advanced Energy Materials.

[23]  T. Unold,et al.  Synergistic Effects of Double Cation Substitution in Solution‐Processed CZTS Solar Cells with over 10% Efficiency , 2018, Advanced Energy Materials.

[24]  M. Green,et al.  Cu2ZnSnS4 solar cells with over 10% power conversion efficiency enabled by heterojunction heat treatment , 2018, Nature Energy.

[25]  O. Hansen,et al.  What is the band alignment of Cu 2 ZnSn(S,Se) 4 solar cells? , 2017 .

[26]  J. Schou,et al.  Ultra-thin Cu2ZnSnS4 solar cell by pulsed laser deposition , 2017 .

[27]  D. Mitzi,et al.  Defect Engineering in Multinary Earth‐Abundant Chalcogenide Photovoltaic Materials , 2017 .

[28]  Weifeng Liu,et al.  Pulsed laser deposition of Cu2ZnSnS4 thin films from single quaternary sulfide target prepared by combustion method , 2016 .

[29]  X. Mathew,et al.  Obtaining phase-pure CZTS thin films by annealing vacuum evaporated CuS/SnS/ZnS stack , 2016 .

[30]  A. Walsh,et al.  Is the Cu/Zn Disorder the Main Culprit for the Voltage Deficit in Kesterite Solar Cells? , 2016 .

[31]  Martin A. Green,et al.  Over 9% Efficient Kesterite Cu2ZnSnS4 Solar Cell Fabricated by Using Zn1–xCdxS Buffer Layer , 2016 .

[32]  M. Capizzi,et al.  Effect of the order-disorder transition on the optical properties of Cu2ZnSnS4 , 2016 .

[33]  J. Larsen,et al.  Optical properties of reactively sputtered Cu2ZnSnS4 solar absorbers determined by spectroscopic ellipsometry and spectrophotometry , 2016 .

[34]  Oki Gunawan,et al.  Photovoltaic Materials and Devices Based on the Alloyed Kesterite Absorber (AgxCu1–x)2ZnSnSe4 , 2016 .

[35]  D. Hewak,et al.  Effect of copper content and sulfurization process on optical, structural and electrical properties of ultrasonic spray pyrolysed Cu2ZnSnS4 thin films , 2016 .

[36]  R. Agrawal,et al.  Optoelectronic and material properties of nanocrystal-based CZTSe absorbers with Ag-alloying , 2016 .

[37]  N. Song,et al.  Band alignments of different buffer layers (CdS, Zn(O,S), and In2S3) on Cu2ZnSnS4 , 2014 .

[38]  Charlotte Platzer-Björkman,et al.  A low-temperature order-disorder transition in Cu2ZnSnS4 thin films , 2014 .

[39]  A. Pérez‐Rodríguez,et al.  Multiwavelength excitation Raman scattering study of polycrystalline kesterite Cu2ZnSnS4 thin films , 2014 .

[40]  S. Zuo,et al.  Comparative study of the influence of two distinct sulfurization ramping rates on the properties of Cu2ZnSnS4 thin films , 2012 .

[41]  D. Mitzi,et al.  Electronic properties of the Cu2ZnSn(Se,S)4 absorber layer in solar cells as revealed by admittance spectroscopy and related methods , 2012 .

[42]  M. Free,et al.  A study of energy band gap versus temperature for Cu2ZnSnS4 thin films , 2011, 1107.3890.

[43]  David L. King,et al.  Solar cell efficiency tables (Version 60) , 1997 .

[44]  X. Hao,et al.  Interface engineering of p-n heterojunction for kesterite photovoltaics: A progress review , 2021 .