Kim Jae Cheon, Rahman Md Mahbubur, Ju Myung Jong, Lee Jae-Joon
Department of Energy Materials and Engineering, Research Center for Photoenergy Harvesting & Conversion Technology (phct), Dongguk University 26 Pil-dong, 3-ga, Jung-gu Seoul 04620 Republic of Korea
Nanotechnology Research Center & Department of Energy and Materials, Konkuk University Chungju 27478 Republic of Korea.
RSC Adv. 2018 May 23;8(34):19058-19066. doi: 10.1039/c8ra02668h. eCollection 2018 May 22.
Platinum (Pt) as the counter electrode (CE) in dye-sensitized solar cells (DSSCs) is expensive and non-optimal for cobalt(ii/iii) redox couples, which can tune and improve the performance of DSSCs, thus motivating the search for replacements of the Pt CE. Graphene nanoplatelets (GnPs) are possible alternatives to Pt CEs but they are mechanically unstable as CEs due to their poor substrate adhesion. Here we report a new type of PEDOT:PSS (PP)/GnP (PPG) composite that maintains the catalytic performance of GnPs with enhanced adhesion to the substrate a conductive PEDOT matrix. The resultant PPG exhibited extremely low charge-transfer resistance ( ) compared to Pt in its role as an electrocatalyst toward a Co(bpy) (bpy = 2,2'-bipyridine) redox couple, and displayed extremely high electrochemical stability for Co(bpy) reduction even after 1000 cycles. The inter-stacking of GnP layers between PEDOT and PSS was confirmed by XPS and Raman spectra. It helps to delocalize charges in the PEDOT backbone and rapidly transfers electrons from the external circuit to Co(bpy) . This reduces the and ultimately improves the photovoltaic performance. The DSSC based on Y123 sensitizer and PPG-CE showed a higher photovoltaic performance of 8.33% than its Pt counterpart does (7.99%) under the optimized conditions.
在染料敏化太阳能电池（DSSC）中，铂（Pt）作为对电极（CE）成本高昂，且对于钴（II/III）氧化还原对并非最优选择，而钴（II/III）氧化还原对可调节并改善DSSC的性能，因此促使人们寻找Pt对电极的替代物。石墨烯纳米片（GnP）是Pt对电极的可能替代物，但由于其与基底的粘附性差，作为对电极时机械稳定性不佳。在此，我们报道了一种新型的聚（3,4-乙撑二氧噻吩）：聚苯乙烯磺酸盐（PEDOT:PSS，简称PP）/GnP（简称PPG）复合材料，该材料在具有增强的与基底（导电的PEDOT基体）粘附性的同时，保持了GnP的催化性能。作为针对Co（bpy） （bpy = 2,2'-联吡啶）氧化还原对的电催化剂，所得的PPG与Pt相比表现出极低的电荷转移电阻（ ），并且即使在1000次循环后，对于Co（bpy） 还原仍表现出极高的电化学稳定性。通过X射线光电子能谱（XPS）和拉曼光谱证实了GnP层在PEDOT和PSS之间的层间堆叠。这有助于使PEDOT主链中的电荷离域，并将电子从外部电路快速转移至Co（bpy） 。这降低了 并最终提高了光伏性能。在优化条件下，基于Y123敏化剂和PPG对电极的DSSC表现出比基于Pt对电极的DSSC更高的光伏性能，前者为8.33%，后者为7.99%。
