Enhanced optoelectronic quality of perovskite thin films with hypophosphorous acid for planar heterojunction solar cells

• DOI: 10.1038/ncomms10030
• Publication Date: 2015-11-30T11:19:55Z
• Authors: Wei Zhang; Sandeep Pathak; Nobuya Sakai; Thomas Stergiopoulos; Pabitra K. Nayak; Nakita K. Noel; Amir A. Haghighirad; Victor M. Burlakov; Dane W. deQuilettes; Aditya Sadhanala; Wenzhe Li; Liduo Wang; David S. Ginger; Richard H. Friend; Henry J. Snaith
• Keywords: 500; General Physics and Astronomy; General Chemistry; 02 engineering and technology; Optoelectronic devices; 540; 7. Clean energy; F100 - Chemistry; Article; General Biochemistry, Genetics and Molecular Biology; F100 Chemistry; 0210 nano-technology; JCOpen

Solution-processed metal halide perovskite semiconductors, such as CH3NH3PbI3, have exhibited remarkable performance in solar cells, despite having non-negligible density of defect states. A likely candidate is vacancies within the crystals, or presence metallic lead, both generated due to imbalanced I/Pb stoichiometry which could evolve during crystallization. Herein, we show that addition hypophosphorous acid (HPA) precursor solution can significantly improve film quality, electronically and topologically, enhance photoluminescence intensity, leads more efficient reproducible photovoltaic devices. We demonstrate HPA reduce oxidized I2 back into I(-), our results indicate this facilitates an improved crystal a reduced lead.