Analysis of Transition Metal Oxides based Heterojunction Solar Cells with S-shaped J-V curves

Abstract

The use of transition metal oxides for the selective carrier contact in the crystalline silicon solar cells technology is rising to interest for the excellent optoelectrical properties of these materials whose implementation, however, can result in lousy performing cells due to an S-shaped electrical characteristic. In this paper, we fabricated solar cells showing S-shaped J-V curve and carried out an analysis of the reasons of such behavior using a model involving the series of a standard cell equivalent circuit with a Schottky junction in order to explain these atypical performances. A good matching between the experimental measurements and the adopted theoretical model was obtained. The extracted parameters are listed and analyzed to shade light on the reasons behind the lowperformance cells.

Facile light exposure of zinc oxide via interfacial engineering for boosting responsivity and detectivity in organic photodetectors

“…18–20 The light exposure effect on metal oxide materials (such as ZnO, SnO 2 and TiO 2 ) has also been reported to have the effect of restoring the ‘S-shape’ of the current–voltage ( J – V ) graph in inverted OPVs. 21–24 This result implies that ZnO has an effect based on light irradiation. 25 Therefore, a study was conducted on improving the photocurrent and suppressing the dark current by introducing light exposure treatment on the ZnO layer, which was confirmed to be closely related to improvements in recombination resistance due to the limitation of defects on the ZnO surface.…”

Density of states characterization of TiO2 films deposited by pulsed laser deposition for heterojunction solar cells

“…Several model have been validated for the solar cells for static and dynamic behavior [85]; however, the S-shape J-V characteristic cannot be explained with a standard model and therefore, a more complex model has been proposed [86,87] modeling the barrier as shown in Fig. 9(b) with a rectifying Schottky junction connected in series with the heterojunction cell top model as in [88] and applied previously to solar cells with TMO-based hole-selective contact [13]. Hence, the model, represented in Fig.…”

“…Therefore, other materials such as the transition metal oxides (TMOs) are currently investigated to replace a-Si:H in HJT and implement passivating carrier selective contacts (CSC) [8]. These contacts are typically made of TMOs like TiO2, ZnO and TaO (for the electron selective contact) [9][10][11], MoO3, WO3 and V2O5 (for the hole selective contact) [12][13][14] and can be deposited reliably with a variety of different techniques such as atomic layer deposition, atmospheric pressure chemical vapor deposition, physical vapor deposition and wet chemical methods [15]. Examples of HJT cells implementing TMOs selective contacts have been reported [7,[16][17][18], reaching efficiency up to 23.5% [19].…”

Characterization of the defect density states in MoOx for c-Si solar cell applications

“…Moreover, the hole selectivity capability of the MoOx is exploited for other classes of electronic devices such as organic lightemitting diodes [3], organic photovoltaic cells [4], thin-film solar cells [5]. Thus, the optimization of this hole-selective layer has been investigated over the past years, highlighting the role of the defect density of states (DOS) [6][7][8]. Nonetheless, information on the DOS, linked to oxygen vacancies [9], lacks for TMOs.…”