Suppression of charge recombination by application of Cu2ZnSnS4-graphene counter electrode to thin dye-sensitized solar cells

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2016,（15）
• 页码范围: 1221-1230
• 页数: 10页
• 语种: 中文
• DOI: 10.1007/s11434-016-1120-0

摘要

This paper proposes a new mechanism to explain the performance of thin dye-sensitized solar cells (DSSC).Near-stoichiometric flower-like Cu2ZnSnS4 (CZTS) microspheres with a high specific surface area was fabricated for use as the photocathode in a DSSC.To improve the extraction and transfer of electrons,graphene was added to the CZTS.A DSSC with a 10-μm TiO2 photoanode layer exhibited a slightly degraded efficiency with a CZTS-graphene photocathode,relative to a Pt counter electrode (CE).Nevertheless,when the thickness of the TiO2 photoanode was reduced to 2 μm,the efficiency of a DSSC with a CZTS-graphene photocathode was greater than that of a Pt-DSSC.It is speculated that,unlike the Pt CE,a CZTS-graphene photocathode not only collects electrons from an external circuit and catalyzes the reduction of the triiodide ions in the electrolyte,but also utilizes unabsorbed photons to produce photo-excited electrons and suppresses charge recombination,thus enhancing the performance of the cell.The use of narrow band gap p-type semiconductors as photocathodes offers a new means of fabricating thin dye-sensitized solar cells and effectively improving the cell performance.