Autodecomposition Approach for the Low-Temperature Mesostructuring of Nanocrystal Semiconductor Electrodes

Templating nanocrystals into mesoporous electrodes using an organic porogen typically requires thermal oxidation at >400 degrees C to completely remove the organic material and afford good electronic properties. These oxidation conditions are incompatible with many NC materials. Here, we demonstrate that nitrocellulose can afford mesoporous CdS and CZTS nanocrystal thin film electrodes at only 250-300 degrees C in air or under argon. Remarkable control over the surface area and the average pore size (20-100 nm) in thin films are demonstrated by varying the ratio of preformed nanocrystals and nitrocellulose. Moreover the mesoporous electrodes exhibit excellent optoelectronic properties. Photoelectrochemical performance is enhanced due to the increased active surface area, showing an 8-fold photocurrent increase over compact nanocrystal films, and an IPCE over 70%.