Performance Optimization of Polymer Solar Cells Using Electrostatically Sprayed Photoactive Layers

Abstract

Polymer solar cells (PSCs) are fabricated using a novel fi lm deposition method, the electrostatic spray (e-spray) technique. Stable atomization and uniform deposition of the polymer blend by e-spray are achieved by manipulating the solution concentration, the solvent composition, and the electric fi eld. The performance of PSCs is primarily infl uenced by the inherent fi lm morphology of the e-sprayed polymer-blend active layers, which is significantly different from that of the conventional fi lms that are formed using the spin-coating (SC) method. The intrinsically formed interfacial boundaries between the e-sprayed blend pancakes resist charge transport, which unfavorably infl uences device effi ciency. The internal series resistance ( R S ) of the PSCs that are formed using the e-spray method (e-spray-PSC) is signifi cantly reduced by a solvent vapor soaking (SVS) treatment in addition to the conventional thermodynamic nanomorphology controls. The detailed relationship between the morphologies (fi lm morphology and internal nanomorphology) and the R S is revealed using impedance spectroscopy. The performance of the e-spray-PSCs is comparable to those of the PSCs that are fabricated using the SC method under identical conditions. Therefore, the e-spray method can be used to fabricate ultralow-cost PSCs, because of the performance results combined with the intrinsic advantages that the e-spray method is simple and has a low materials loss.

Improved UV sensitivity and charge transport in PTB7-Th:PC 71 BM solar cells doped with cadmium selenide quantum dots

“…R CT was mainly caused by the charge-transport resistance at the blend active layer/electrode interfaces and/or inside the blend active layer. 32,33 All the devices show similar R Ω , which is corresponding to the results from the AFM images. The R CT values of the PSCs decrease significantly after doping CdSe QDs, from 29.52 Ω cm 2 for the devices without CdSe QDs to 17.96, 15.96 and 14.12 Ω cm 2 for the devices with CdSe QDs at 623 nm, 525 nm, and 462 nm, respectively.…”

Improved Power Conversion Efficiency of Organic Photovoltaic Cell Fabricated by Electrospray Deposition Method by Mixing Different Solvents

“…Recently, Kim et al reported an OPV fabricated by the ESD method. 24) The reported device performance is almost same as that of the reference device fabricated by the spin-coating process. However, the solvent vapor soaking technique is necessary to reduce the surface roughness of the poly(3-hexylthiophene) (P3HT)-doped-(6,6)-phenyl-C61-butyric acid methyl ester (PCBM) layer.…”

Film forming properties of electrosprayed organic heterojunctions

“…On the other hand, the open-circuit voltage (V oc ) did not change relevantly (0.40-0.55 V) for both sets of devices, because the V oc mainly depends on the electronic donor/acceptor energy levels [10]. From these results it is evident that the PCE of electrosprayed devices obtained here is almost four times larger than the corresponding electrostatically sprayed devices without any further treatment obtained by Kim and coworkers [16] because of the specific parameters allowed by the present setup. Table 1 summarizes the characteristics of the devices obtained in this study.…”