High performance polythiophene/fullerene bulk-heterojunction solar cell with a TiOx hole blocking layer

Abstract

Insertion of a TiOx layer between the Al electrode and the active layer of an organic photovoltaic cell resulted in a high performance with 94% durability under irradiation (100mW∕cm2) for 100h and had improved fill factor and open circuit voltage. An efficiency of 4.05% was achieved by using the cell containing a TiOx layer fabricated and measured in ambient atmosphere. The TiOx layer works as an effective barrier to physical damage and chemical degradation, resulting in high durability under aerobic conditions, and also serves as a hole blocking layer, resulting in improved parallel resistance and rectification.

Understanding the effect of ferroelectric polarization on power conversion efficiency of organic photovoltaic devices

“…This weak decay in principle may be caused by a slight depolarization of P(VDF-TrFE), but more likely to be induced by other factors such as degradation of the semiconductor polymers and oxidation of the electrodes, since the devices without the ferroelectric layer also show a similar degradation rate in our lab and those reported elsewhere. [27][28][29] During the stability test, the devices were kept in the dark and the whole poling process was conducted in the dark.…”

Highly durable inverted-type organic solar cell using amorphous titanium oxide as electron collection electrode inserted between ITO and organic layer

“…Whereas, the performance of the cell with EA-TiO x layer showed J sc = 6.70 mA cm -2 , V oc = 0.56 V, FF = 0.55, and η = 2.06 %, see curve (a) in Figure 2, the η value being 2.5 times higher than that without TiO x layer. This result suggests an improvement of the rectification of the device, because the TiO x layer acts as an electron collection layer and a hole blocking layer [8,23]. Figure 3 shows the photo I-V curves of the solar cells with the various TiO x thin films, and the cell performance is summarized in Table 1.…”

Incremental optimization in donor polymers for bulk heterojunction organic solar cells exhibiting high performance

“…Optical spacers can enhance the absorption efficiency with fixed thickness of active layer and result in an increased photocurrent. 91 For example, Heeger et al optimized the performance of BHJ devices based on PCDTBT by introducing a TiO x layer between the aluminum and the active layer, which enhanced the optical absorption without requiring thicker active-layers. The PCE of the device increased to 6.2% (5.96% certified by NREL) upon introduction of the TiO X layer.…”