Transient characteristics of inverted polymer solar cells using titaniumoxide interlayers

Abstract

Organic bulk heterojunction solar cells using titania interlayers as electron selective layers prepared by atomic layer deposition or wet processing are reported. Pristine devices show low filling factors (FFs) and consequently low efficiencies. Upon illumination with ultraviolet (UV) light, a significant increase in the FF is found. We study the impact of various ambient conditions (air, vacuum, and oxygen) on the dynamics of the decay of the FF after UV illumination. The interaction of oxygen and titania is evidenced as the dominant mechanism for the transient behavior of the polymer solar cells.

Direct observation of UV-induced charge accumulation in inverted-type polymer solar cells with a TiOx layer: Microscopic elucidation of the light-soaking phenomenon

“…When the device was irradiated by white light, the cell performance greatly improved, showing a proper J-shaped J-V curve, and the curve then maintained the J-shape under irradiation of both white light and brief UV-cut light. [8][9][10][11][12][13]15 Direct evidence for the light-soaking-induced charge accumulation is demonstrated by ESR measurements. In these experiments, a continuous-wave method was used with a modulation frequency of 100 kHz for the external magnetic field H. 18 Thus, the observed light-induced ESR signals are due to accumulated (or deeply trapped) photogenerated charge carriers with a lifetime of >10 ls.…”

“…[3][4][5][6][7] One of the fundamental issues is the light-soaking phenomenon with respect to UV-light irradiation, which has been commonly observed in IOSCs with electron-collecting layers such as TiO x . 2,[8][9][10][11][12][13][14][15] Although high-temperature annealing treatments on the TiO x layer can prevent the phenomenon, such treatments are undesirable for low-temperature device fabrication using flexible plastic substrates. 15 Additionally, long-term UV-light irradiation on IOSCs can cause device degradation.…”

Facile preparation of TiOXfilm as an interface material for efficient inverted polymer solar cells

“…), and the ITO coated glass as the cathode is modied using stable n-type metal oxides such as titanium oxide (TiO X ), [18][19][20][21][22][23][24][25] zinc oxide (ZnO), [26][27][28] and cesium carbonate (Cs 2 CO 3 ).…”

Metal oxide semiconducting interfacial layers for photovoltaic and photocatalytic applications

“…The UV-activated TiO 2 films are shown to degrade much rapidly under continuous illumination during regular operating conditions. The UV light causes photodoping of TiO 2 where oxygen is chemisorbed at those sites, leading to unfavorable band bending in the TiO 2 and thereby hindering charge extraction [78]. UV photodoping is one of the prime issues to be solved to use it in OSCs as the ETL layer efficiently.…”