Solvothermal synthesis of ZnO nanoparticles at low temperatures as cathode buffer layers for polymer solar cells with an inverted device structure

Abstract

Inverted polymer solar cells of the conventional poly(3-hexylthiophene) (P3HT):(6,6)-phenyl-C61butyric acid methyl ester (PC 61 BM) blend on indium tin oxide substrates were fabricated. By using mixed-solvent dispersed ZnO nanoparticles (NPs) as cathode buffer layer, device performances are improved obviously. ZnO NPs with a size of 3-5 nm synthesized by solvothermal synthesis at 65°C show relatively wide photoluminescence peak of 300-650 nm. Based on Hansen solubility parameter theory, a mathematical method was applied to calculate the Hansen solubility parameters of bi-solvent system to disperse ZnO NPs and the proportion of each component in the mixed solvent. This excellent dispersion for ZnO NPs in the bi-solvent system has a important influence on the performance of the device. Compared to other methods of ZnO nanofilm fabrication, this method reveals a simple, convenient, moderate and effective way to manufacture the favorable buffer layer in organic solar cells.

A competitive reaction strategy toward dielectric phases for enhancing electromagnetic wave absorption of polymer-derived ceramics

“…When RL is less than −10 dB, more than 90% of the EW is lost, and the corresponding frequency band is defined as the EAB. 27–29 The smaller the value of RL, the larger the proportion of EMW lost. To obtain low RL and large EAB, good impedance matching and high dielectric loss performance are important factors.…”