Solution-processable polymer solar cells from a poly(3-hexylthiophene)/[6,6]-phenyl C61-butyric acidmethyl ester concentration graded bilayers

Abstract

Polymer photovoltaic (PV) device prepared with a vertical phase separation has intensified the research on the effectiveness of the concentration graded active layer. In this paper, a polymer PV device with a poly(3-hexylthiophene)/[6,6]-phenyl C61-butyric acidmethyl ester (P3HT/PCBM) bilayers active film with a concentration gradient has been fabricated via solution process. The concentration variation has been confirmed by the Auger spectroscopy. The devices showed an enhanced photocurrent density and power conversion efficiency compared to those of the bulk heterojunction PV prepared under the same fabrication condition.

Improved polymer solar cell performance by engineering of cathode interface

“…10. The schematic illustration for the energy-level diagram of the various materials and electrodes used in the experiments, presented with their work function, HOMO and LUMO values in electron volt (eV) were taken from the references elsewhere [22,[30][31][32][33].…”

Enhanced performance of layer-evolved bulk-heterojunction solar cells with Ag nanoparticles by sequential deposition

“…Ag atoms are obtained by reducing AgNO 3 with 1,2-propanediol in the existence of deionized water, through the following reactions [33][34][35][36][37]: of over 2 wt%, the J SC value is reduced with that of the optimized ratio of Ag NPs in LE-BHJ device, and a similar V OC with a slightly increased FF obtained as summarized in Table 2. The LE-BHJ with Ag NPs exhibited slight lower FF value than the plain BHJ devices due to the possibility of different PC 71 BM concentration and interfaces with concentration gradient within the active layer during the sequential processing of top (acceptor) layer penetration to the pre-deposited bottom (donor) layer [19,21,38]. However, the important factors that increase the PCE of the device are J SC (increased from 12.48 mA/cm 2 to 14.64 mA/cm 2 ) in 30 nm-sized NPs based Ag embedded LE-BHJ film (2 wt%).…”

“…According to several recent reports, promising bilayer structured solar cells have been fabricated by using inter-diffusion of acceptor materials of the top layer into the donor material based bottom layer, via different solvent or thermal annealing [19][20][21]. However, while the bilayer structured solar cells demonstrate a better nanoscale morphology, and solve PCBM top layer aggregation by a sequential deposition process, the power conversion efficiency (PCE) (%) of the organic solar cells exhibits only similar or comparable efficiency, compared to the conventional BHJ and LE-BHJ.…”

“…In order to improve the performance of the OPV device, various fabrications and researches have been carried out, such as the thermal and solvent annealing processes [11][12][13][14], insertion of interlayers for efficient transport [15][16][17][18], and layer-evolved heterojunction (LE-BHJ) for spontaneous interdiffusion [19][20][21].…”

Efficiency improvement in organic solar cells by inserting a discotic liquid crystal

“…It is a useful method to improve the efficiency of bulk heterojunction P3HT: PCBM photovoltaic devices by inserting interfacial layers in OSCs based on P3HT:PCBM blended layer. For example, Wang et al [9] attained better J SC by inserting P3HT between hole transport layer and active layer, while inserting PCBM between active layer and cathode. Zhang et al [10] inserted copper phthalocyanine layer between poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and P3HT:PCBM blended layer to increase J SC .…”