A Printable Organic Electron Transport Layer for Low‐Temperature‐Processed, Hysteresis‐Free, and Stable Planar Perovskite Solar Cells. Issue 15 (20th April 2017) - Lee, Jinho
Abstract : Despite recent breakthroughs in power conversion efficiencies (PCEs), which have resulted in PCEs exceeding 22%, perovskite solar cells (PSCs) still face serious drawbacks in terms of their printability, reliability, and stability. The most efficient PSC architecture, which is based on titanium dioxide as an electron transport layer, requires an extremely high‐temperature sintering process (≈500 °C), reveals hysterical discrepancies in the device measurement, and suffers from performance degradation under light illumination. These drawbacks hamper the practical development of PSCs fabricated via a printing process on flexible plastic substrates. Herein, an innovative method to fabricate low‐temperature‐processed, hysteresis‐free, and stable PSCs with a large area up to 1 cm 2 is demonstrated using a versatile organic nanocomposite that combines an electron acceptor and a surface modifier. This nanocomposite forms an ideal, self‐organized electron transport layer (ETL) via a spontaneous vertical phase separation, which leads to hysteresis‐free, planar heterojunction PSCs with stabilized PCEs of over 18%. In addition, the organic nanocomposite concept is successfully applied to the printing process, resulting in a PCE of over 17% in PSCs with printed ETLs. Abstract : An innovative method for achieving printable planar heterojunction perovskite solar cells (PSCs) is demonstrated using self‐assembled organic nanocomposites of fullerene derivatives and cationic polyelectrolytes as the electron transport layer. Highly reliable and stable PSCs with low‐temperature solution‐processable organic nanocomposites exhibit stabilized power conversion efficiencies exceeding 18%.