CH3NH3PbI3 Perovskite-Fullerene Planar-Heterojunction Hybrid Solar Cells.pdfVIP

www.advmat.de www.MaterialsV C O M M U N IC A TI Jun-Yuan Jeng , Yi-Fang Chiang , Mu-Huan Lee , Shin-Rung Peng , Tzung-Fang Guo , * Peter Chen , * and Ten-Chin Wen CH 3 NH 3 PbI 3 Perovskite/Fullerene Planar-Heterojunction Hybrid Solar Cells O N Recent studies have reported organometal halide perovskite- based mesoscopic solar cells with promising photovoltaic effi - ciencies. [ 1–4 ] These devices employ a submicrometer, crystalline, and well-oriented thin fi lm of organo-lead iodide perovskite as the light absorber (or as both light absorber and carrier con- ductor) deposited on the surface of meso-structured titanium dioxide (TiO 2 ) or aluminum oxide (Al 2 O 3 ) layers through a simple spin-coating process. [ 3 , 4 ] Organo-lead iodide perovskite exhibits a direct bandgap and a broad range of light absorption covering the visible to near-infrared spectrum as well as a high extinction coef- fi cient. [ 2 , 4 ] All-solid-state mesoscopic solar cells with organo-lead iodide perovskite as the light absorber exhibit high power conver- sion effi ciencies (PCEs) of great potential in real applications. [ 4 ] Etgar et al. recently reported that spin-casting a methyl- ammonium lead iodide (CH 3 NH 3 PbI 3 ) solution on a 400 nm thick TiO 2 (anatase) nanosheet forms a mesoscopic (CH 3 NH 3 PbI 3 )/TiO 2 heterojunction. [ 5 ] CH 3 NH 3 PbI 3 perovskite successfully acts as both light harvester and hole conductor. No additional hole transport layer is needed in their study. These devices eliminate the diffi culty of infi ltrating a hole conductor, such as 2,2 ′ ,7,7 ′ -tetrakis-( N , N -di- p -methoxyphenyl-amine)-9,9 ′ - spirobifl uorene (spiro-OMeTAD), in mesoporous TiO 2 for the fabrication of all-solid-state devices. [ 6 , 7 ] Generally speaking, dual function (i.e., light absorber and carrier conductor) active layers are widely used in fabricating polymer-, organic-, and inorganic-based solar cells. [ 8–13 ] In other words, the func