Sartorio Camillo, Giuliano Giuliana, Scopelliti Michelangelo, Vetri Valeria, Leone Maurizio, Pignataro Bruno
Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, V.le delle Scienze Ed. 17, 90128, Palermo, Italy.
Phys Chem Chem Phys. 2020 Apr 29;22(16):8344-8352. doi: 10.1039/d0cp00336k.
In this paper, we developed different three-component organic heterojunction structures supported by PET/ITO substrates with the aim to study the possible synergies and/or compromises between charge transfer (CT) and energy transfer (ET) processes in organic solar cells (OSCs). As components, we employed poly(3-hexylthiophene-2,5-diyl) (P3HT; donor), [6,6]-phenyl-C61-butyric acid methyl ester (PCBM; acceptor) and poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) that is known to give good ET to P3HT. At first, we observed that in a planar heterojunction (PHJ) solar cell, F8BT has to be properly located in between P3HT and PCBM to get a cascade energy level configuration allowing for a better CT and power conversion efficiency. Then, we observed that by producing a P3HT:F8BT blend, the energy transfer process can be improved in the P3HT:F8BT/PCBM active layer. This may enable decreasing the thickness of the active layer while maintaining a similar PCE that is very interesting for the development of transparent OSCs. However, the P3HT:F8BT blend limits the P3HT-PCBM CT with respect to a P3HT/F8BT/PCBM PHJ, showing that a compromise between CT and ET is needed to get a higher PCE or higher transparency. By the above approach, in this paper, we developed highly transparent heterojunction structures for solar cell devices with PCEs comparable to those observed from the colorful reference P3HT/PCBM PHJ solar cells on PET/ITO substrates.
在本文中，我们开发了由PET/ITO衬底支撑的不同三元有机异质结结构，旨在研究有机太阳能电池（OSC）中电荷转移（CT）和能量转移（ET）过程之间可能的协同作用和/或折衷。作为组件，我们使用了聚（3-己基噻吩-2,5-二基）（P3HT；供体）、[6,6]-苯基-C61-丁酸甲酯（PCBM；受体）和聚（9,9-二辛基芴-alt-苯并噻二唑）（F8BT），已知其能向P3HT提供良好的ET。首先，我们观察到在平面异质结（PHJ）太阳能电池中，F8BT必须正确地位于P3HT和PCBM之间，以获得级联能级配置，从而实现更好的CT和功率转换效率。然后，我们观察到通过制备P3HT:F8BT共混物，可以在P3HT:F8BT/PCBM活性层中改善能量转移过程。这可能使得在保持相似的功率转换效率（PCE）的同时减小活性层的厚度，这对于透明OSC的开发非常有意义。然而，相对于P3HT/F8BT/PCBM PHJ，P3HT:F8BT共混物限制了P3HT-PCBM的CT，表明为了获得更高的PCE或更高的透明度，需要在CT和ET之间进行折衷。通过上述方法，在本文中，我们开发了用于太阳能电池器件的高透明异质结结构，其PCE与在PET/ITO衬底上观察到的彩色参考P3HT/PCBM PHJ太阳能电池相当。
