Codependence between Crystalline and Photovoltage Evolutions in P3HT:PCBM Solar Cells Probed with in-Operando GIWAXS

Abstract

We address the correlation between the crystalline state of photoactive materials in a model organic solar cell based on poly(3-hexylthiophene-2,5-diyl):phenyl-C-butyric acid methyl ester (P3HT:PCBM) and the photovoltage in an in-operando investigation. I-V curves are simultaneously measured together with grazing incidence wide-angle X-ray scattering probing the crystalline state of the device active layer as a function of the operation time. The results show a high degree of correlation between open-circuit voltage V and the crystalline state of P3HT.

In-line, roll-to-roll morphology analysis of organic solar cell active layers

“…From these observations, it would appear that wettability and higher viscosity of the solution may be more important for R2R coated solar cell performance than the degree of crystallinity of the polymer. This may seem at odds with earlier work, as for instance recently published results by Moseguí González et al 15 , where a clear correlation between polymer crystallinity and solar cell performance was presented. However, this study only considered P3HT on glass, and the disagreement therefore illustrates the need to investigate different kinds of polymers, especially those determined to perform better in R2R coating, to achieve a complete understanding of the conditions leading to optimized solar cell performance.…”

“…However, this study only considered P3HT on glass, and the disagreement therefore illustrates the need to investigate different kinds of polymers, especially those determined to perform better in R2R coating, to achieve a complete understanding of the conditions leading to optimized solar cell performance. An interesting addition to the measurements presented here would be an absolute determination of crystallinity, in lieu of the study by Moseguí González et al 15 , but this is impossible to perform in situ with the current setup, and is instead considered for future studies. Fig.…”

Light‐Induced and Oxygen‐Mediated Degradation Processes in Photoactive Layers Based on PTB7‐Th

“…[ 11–15 ] In particular, the morphological aging process was followed in situ during operation of the respective solar cells using X‐ray scattering methods in earlier works of our group. [ 16–21 ] Chemical reactions, in contrast, were investigated using spectroscopy methods such as ultraviolet–visible (UV–vis) absorption or photoluminescence as well as Raman and Fourier transform infrared (FTIR) spectroscopy. [ 22–25 ] However, research so far has neglected potential interconnections between chemical and structural changes.…”

Design Rule for Improved Open-Circuit Voltage in Binary and Ternary Organic Solar Cells

“…There has been extensive and valuable work on the effect of the material crystallinity on the energetic disorder and therefore on the device Voc. [15][16][17][18][19][20] Results that are both encouraging and puzzling have been obtained. [21][22][23][24] In particular, the mechanism underlying the quasi-linear tunability of the open-circuit voltage (VOC) in both D:A1:A2 and D1:D2:A devices is still heavily debated, hampering a rational search for optimal ternary BHJs.…”