Efficiency above 6% in poly(3‐hexylthiophene):phenyl‐C‐butyric acid methyl ester photovoltaics via simultaneous addition of poly(3‐hexylthiophene) based grafted graphene nanosheets and hydrophobic block copolymers

Abstract

A combination of reduced graphene oxide (rGO) nanosheets grafted with regioregular poly(3-hexylthiophene) (P3HT) (rGO-g-P3HT) and P3HT-b-polystyrene (PS) block copolymers was utilized to modify the morphology of P3HT:[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) active layers in photovoltaic devices. Efficiencies greater than 6% were acquired after a mild thermal annealing. To this end, the assembling of P3HT homopolymers and P3HT-b-PS block copolymers onto rGO-g-P3HT nanosheets was investigated, showing that the copolymers were assembled from the P3HT side onto the rGO-g-P3HT nanosheets. Assembling of P3HT-b-PS block copolymers onto the rGO-g-P3HT nanosheets developed the net hole and electron highways for charge transport, thereby in addition to photoluminescence quenching the charge mobility ( h and e ) values increased considerably. The best charge mobilities were acquired for the P3HT 50000 :PC71BM:rGO-g-P3HT 50000 :P3HT 7000 -b-PS 1000 system ( h = 1.9 × 10 −5 cm 2 V -1 s -1 and e = 0.8 × 10 −4 cm 2 V -1 s -1 ). Thermal annealing conducted at 120 ∘ C also further increased the hole and electron mobilities to 9.8 × 10 −4 and 2.7 × 10 −3 cm 2 V -1 s -1 , respectively. The thermal annealing acted as a driving force for better assembly of the P3HT-b-PS copolymers onto the rGO-g-P3HT nanosheets. This phenomenon improved the short circuit current density, fill factor, open circuit voltage and power conversion efficiency parameters from 11.13 mA cm −2 , 0.63 V, 62% and 4.35% to 12.98 mA cm −2 , 0.69 V, 68% and 6.09%, respectively. RESULTS AND DISCUSSION Synthesis P3HT homopolymerFourier transform IR (FTIR) spectra of P3HT-Br and 1 H NMR spectra of P3HT 7000 and P3HT 50000 are shown in Figs S1(a)-S1(c), Polym Int 2019; 68: 1292-1302

Molecular Orientations at Buried Conducting Polymer/Graphene Interfaces

“…Due to their excellent properties such as optoelectronic designability, low-cost solution processability, and polymeric flexibility, semiconducting polymers have been extensively researched for many applications in OFETs, , printable integrated circuits, , wearable ultralight sensors, , large-area photovoltaic devices, ,, etc. For example, it was demonstrated that semiconducting conjugate polymer-based solar cells can reach high power conversion efficiencies (PCEs), around 6%. − However, the low charge carrier mobilities for semiconducting polymers still restrict their practical applications. It is believed that integrating semiconducting polymers with high-performance conductors is one feasible approach to overcome this barrier.…”

Tackling Performance Challenges in Organic Photovoltaics: An Overview about Compatibilizers

“…In the paper from Xu and coworkers [143], they describe an OPV based on the classic architecture P3HT:PCBM, where a compatible low-bandgap polymer is added, PCBTDPP, in order to act as a "bridge" between the main donor and acceptor units, Block copolymers incorporating both P3HT and poly(styrene) portions are well-known polymeric CBs, widely reported to improve the morphology of P3HT blends in combination with PCBM [140] or other fulleropyrrolidine derivatives [141]. An "exotic" approach has been recently referred to by Mohammadi-Arbati and colleagues, who have reported the combined addition of a rod-coil block copolymer comprising P3HT and polystyrene (P3HT-b-PS), and reduced graphene oxide nanosheets grafted with regioregular poly(3-hexylthiophene) (rGO-g-P3HT) as compatibilizers in a typical P3HT:PCBM blend [142]. A combination of data acquired by XPS, TEM, and AFM supports the hypothesis that the CB localizes at the interface, with P3HT portions from the copolymer interacting with the P3HT residues grafted onto rGO-g-P3HT.…”

Polymer/quantum dot nanostructures in remarkably stabilized photovoltaics based on polymers having benzodithiophene/naphthothiadiazole constituents

“…Some researchers have utilized distinct agents in organic photovoltaics to stabilize the morphology of active layers. [10][11][12][13][14][15][16][17][18][19][20][21] In this regard, the polymer/quantum dot (QD) compositions have retained attention for the morphological and structural manipulations in photovoltaics. [22][23][24][25][26][27][28][29][30] For having the proper carrier generation, cheapness, and optical activities depending on size, the 2 | EXPERIMENTAL CQD preparation.…”