Beyond Metal Oxides: Introducing Low‐Temperature Solution‐Processed Ultrathin Layered Double Hydroxide Nanosheets into Polymer Solar Cells Toward Improved Electron Transport

Abstract

Metal oxides such as zinc oxide (ZnO) have been commonly used as the cathode interfacial layer (CIL) of bulk heterojunction inverted polymer solar cells (BHJ‐iPSCs), for which a high‐temperature annealing treatment is usually required to improve their CIL performance. Layered double hydroxides (LDHs) are a class of inorganic two‐dimensional (2D) nanomaterials composed of positively charged brucite‐like layers intercalated with charge‐balancing anions and water molecules, showing potential applications in catalysis, adsorption, electrochemical energy storage and conversion, etc., but have never been applied in PSCs. Herein, for the first time LDH nanosheets are applied in BHJ‐iPSC devices as a novel CIL substituting the commonly used ZnO, affording an obvious efficiency enhancement relative to ZnO‐based device. Ultrathin MgxAl‐NO3‐LDH nanosheets are prepared by ultrasonication‐assisted liquid exfoliation of bulk MgxAl‐NO3‐LDHs prepared via a co‐precipitation method, and deposited onto an ITO substrate as a CIL by a low‐temperature solution‐processed technique. Based on MgxAl‐NO3‐LDH CIL, BHJ‐iPSC devices with the poly(4,8‐bis‐alkyloxybenzo(l,2‐b:4,5‐b′)‐dithiophene‐2,6‐diylalt‐(alkylthieno(3,4‐b) thiophene‐2‐carboxylate)‐2,6‐diyl):[6,6]‐phenyl C71‐butyric acid methyl ester (PBDTTT‐C:PC71BM) photoactive layer exhibits an improvement of power conversion efficiency relative to those based on ZnO CIL. This is primarily originated from the increase of fill factor due to the improved interfacial contact between the ITO and active layer, facilitating the interfacial electron transport.

Preparation and High Photocurrent Generation Enhancement of Self-Assembled Layered Double Hydroxide-Based Composite Dye Films

“…Layered double hydroxide (LDH) has a special double hydroxide structure. The main part is usually composed of any two metal oxidation states (positive divalent, positive trivalent, or positive tetravalent) adjusted in different ratios, and the other part is composed of hydroxyl and anion. , Its two-dimensional structure has an excess of a positively charged layered structure, and the positive charge number is twice that of the self-valence positive ion. Excess positive interlayer charges can complement the anions in the middle of the layer .…”

Nanoscale control of grain boundary potential barrier, dopant density and filled trap state density for higher efficiency perovskite solar cells

“…Perovskite solar cells (PSC) have attracted remarkable attention owing to their interesting material properties of metal‐organic halide perovskites such as high absorption coefficients, tunable optical band gap, long range carrier diffusion lengths (100‐1000 nm), small exciton binding energy, and ambipolar charge transport . The power conversion efficiency (PCE) of perovskite‐based solar cells has increased drastically during the past several years . Organolead halide perovskite materials have been used as the active material in a range of optoelectronic device based applications such as light emitting devices, photodetectors etc.…”

“…[1][2][3][4][5][6][7][8] The power conversion efficiency (PCE) of perovskite-based solar cells has increased drastically during the past several years. [9][10][11][12][13] Organolead halide perovskite materials have been used as the active material in a range of optoelectronic device based applications such as light emitting devices, photodetectors etc. However, the understanding of the fundamental material properties of organolead halide perovskite and device operation in varied humidity is still limited.…”