Eliminating the Detrimental Effect of Secondary Doping on PEDOT : PSS Hole Transporting Material Performance

Abstract

Secondary doping has a long history of use in conductivity enhancement in poly (3,4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS). However, very little research has addressed its detrimental effect on application performance of PEDOT : PSS in organic solar cells. Herein, it was shown that the uneven drying of secondary dopant-water mixture results in a nonuniform/continuous film structure, causing severe damage to the device efficiencies (dropping about 8 and 23 % for poly [(2,6-(4,8-bis(5-(2-ethylhexyl) and poly[(2,6-(4,8-bis(5-(2) cells, respectively) and thermal stabilities. Moreover, a simple yet robust dialysis treatment was proposed to solve the issue of noncontinuity and retain the secondary doping's advantages of quinoid structure simultaneously, thus demonstrating a significant enhancement in device performance. This study will be of great importance to the future exploration of the next generation of post-treatment strategy.

Template molecular weight-dependent PEDOT surface energy: impact on the photovoltaic performance of bulk-heterojunctions

“…The total γ s values of PEDOT:PSS films were estimated by the surface wettability-based Owens–Wendt method. 9,38 As illustrated in Fig. 3a, the water contact angles on the surfaces of P-70, P-200, P-500 and P-1000 films are 42.68°, 60.38°, 80.13° and 91.52°, respectively, while the corresponding diiodomethane (DIM) contact angles are 43.14°, 60.13°, 60.42° and 64.79°, respectively.…”

“…[1][2][3][4][5][6] The design of anode interfacial materials (AIMs) is equally important, not only for improving the efficiency of charge collection at the anode interface but also for optimizing the morphology of photoactive BHJs. [7][8][9][10] Regrettably, the development of AIMs is still far behind. [11][12][13] The poly (3,4-ethylenedioxythiophene):polystyrene sulfonic acid (PEDOT:PSS) conducting polymer, invented in the early 1990s, is still the most frequently utilized AIM in conventional OSCs so far.…”

“…1–6 The design of anode interfacial materials (AIMs) is equally important, not only for improving the efficiency of charge collection at the anode interface but also for optimizing the morphology of photoactive BHJs. 7–10 Regrettably, the development of AIMs is still far behind. 11–13…”

“…Recently, surface energy ( γ s ) regulation on PEDOT:PSS AIM using the secondary doping strategy is becoming increasingly popular in the morphological control of BHJs and realizing high performance OSCs. 9,14–19 For example, Zhou et al 20 mixed WO x nanoparticles into PEDOT:PSS to improve the γ s of the AIM and to optimize the phase separation of BHJs, leading to a significantly enhanced efficiency. Despite progress, effective strategies allowing for a continuous regulation on the γ s of PEDOT:PSS for meeting the requirements of various BHJs are still lacking so far.…”

Kinetic control in the synthesis of highly conductive solution-processable PEDOTs

“…[1][2][3][4][5][6][7][8][9][10] With the recent rapid advancements in organic electronic devices, the electronic properties of the PEDOT:PSS CP, particularly its conductivity, appear to be somewhat inadequate, posing a gradual obstacle for the further development of organic electronics. [11][12][13][14][15] Therefore, there is a pressing need to enhance the conductive performance of PEDOT:PSS CPs. [16][17][18][19][20][21][22] The PEDOT:PSS CP is typically synthesized through the oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) in an aqueous solution containing PSS polyanions.…”