Low-Temperature Solution-Processed Perovskite Solar Cells with High Efficiency and Flexibility

TLDR

Perovskite photovoltaics have attracted attention, but conventional TiO₂ electron‑transport layers require high‑temperature (≈450 °C) processing that limits widespread adoption. This study introduces a low‑temperature (<120 °C) processing approach to fabricate high‑efficiency perovskite solar cells on both rigid and flexible substrates. Devices were fabricated by solution‑processing a mixed‑halide perovskite (CH₃NH₃PbI₃₋ₓClₓ) with PEDOT:PSS as the hole transport layer and PCBM as the electron transport layer on a substrate/ITO/PEDOT:PSS/CH₃NH₃PbI₃₋ₓClₓ/PCBM/Al stack, all deposited below 120 °C. The resulting cells achieved 11.5 % power‑conversion efficiency on glass/ITO and 9.2 % on PET/ITO flexible substrates.

Abstract

Perovskite compounds have attracted recently great attention in photovoltaic research. The devices are typically fabricated using condensed or mesoporous TiO2 as the electron transport layer and 2,2'7,7'-tetrakis-(N,N-dip-methoxyphenylamine)9,9'-spirobifluorene as the hole transport layer. However, the high-temperature processing (450 °C) requirement of the TiO2 layer could hinder the widespread adoption of the technology. In this report, we adopted a low-temperature processing technique to attain high-efficiency devices in both rigid and flexible substrates, using device structure substrate/ITO/PEDOT:PSS/CH(3)NH(3)PbI(3-x)Cl(x)/PCBM/Al, where PEDOT:PSS and PCBM are used as hole and electron transport layers, respectively. Mixed halide perovskite, CH(3)NH(3)PbI(3-x)Cl(x), was used due to its long carrier lifetime and good electrical properties. All of these layers are solution-processed under 120 °C. Based on the proposed device structure, power conversion efficiency (PCE) of 11.5% is obtained in rigid substrates (glass/ITO), and a 9.2% PCE is achieved for a polyethylene terephthalate/ITO flexible substrate.