Humidity controlled sol-gel Zr/TiO2 with optimized band alignment for efficient planar perovskite solar cells

Tongle Bu, Min Wen, Haiyuan Zou, Junqing Wu, Peng Zhou, Wangnan Li, Zhiliang Ku, Yong Peng, Qi Li, Fuzhi Huang, Yi Bing Cheng, Jie Zhong

Research output: Contribution to journalArticleResearchpeer-review

21 Citations (Scopus)

Abstract

This work draws attention to environmental influence to function layers interfaces and the band alignment optimization of organic-inorganic metal halide planar perovskite solar cell (PSC), demonstrating an effective route to enhance the PSC photovoltaic conversion efficiency (PCE) and stability. The PCE of the PSC presents a sensitive correlation with the relative humidity (RH) during the electron transport layer (ETL) preparation. Through optimizing the RH condition, the PSCs show outstanding performances using sol-gel TiO2 ETL prepared under 55 RH%. Moreover, we systematically investigate the Zr doping effect in the TiO2 ink with a variation of Zr molar percentages from 0% to 7.5%. A high PCE of 15.06% with a good fill factor of 0.76 is obtained at 2 mol% Zr doping, in contrast to 12.25% of the undoped device. The Mott-Schottky analysis reveals that the elevated open-circuit voltage (Voc) is attributed to the upshifting of flat band potential of TiO2 from −4.15 eV to −4.02 eV (vs. vacuum) after doping. Notably, the as-made cell shows low hysteresis and elevated stability with only 15% degradation of PCE (35% for PSC with pyrolyzed TiO2) after 550 h/14 RH% ageing without encapsulation.

Original languageEnglish
Pages (from-to)290-296
Number of pages7
JournalSolar Energy
Volume139
DOIs
Publication statusPublished - 1 Dec 2016

Keywords

  • Humidity controlled sol-gel
  • Perovskite solar cell
  • TiO
  • Zr-doping

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