Interfacial Engineering of Cu₂O Passivating Contact for Efficient Crystalline Silicon Solar Cells with an Al₂O₃ Passivation Layer

Abstract

Passivating contacts that simultaneously promote carrier selectivity and suppress surface recombination are considered as a promising trend in the crystalline silicon (c-Si) photovoltaic industry. In this work, efficient p-type c-Si (p-Si) solar cells with cuprous oxide (Cu 2 O) hole-selective contacts are demonstrated. The direct p-Si/Cu 2 O contact leads to a substoichiometric SiO x interlayer and diffusion of Cu into the silicon substrate, which would generate a deep-level impurity behaving as carrier recombination centers. An Al 2 O 3 layer is subsequently employed at the p-Si/Cu 2 O interface, which not only serves as a passivating and tunneling layer but also suppresses the redox reaction and Cu diffusion at the Si/Cu 2 O interface. In conjunction with the high work function of Au and the superior optical property of Ag, a power conversion efficiency up to 19.71% is achieved with a p-Si/Al 2 O 3 /Cu 2 O/Au/Ag rear contact. This work provides a strategy for reducing interfacial defects and lowering energy barrier height in passivating contact solar cells.

Cleaner one-pot transformation of glycerol to acrylic acid and 1,2-propanediol over bifunctional Cu2O/montmorillonite catalysts without external oxygen and hydrogen

“…In detail, the peaks located at ∼932 and ∼952 eV were attributed to the Cu 2p 1/2 and Cu 2p 3/2 binding energy, respectively. 64 According to the fitting results, the peak at ∼932 eV consists of two partially overlapped peaks located at 932.5 and 934.9 eV, which were ascribed to the binding energy of Cu 0 or Cu + and Cu 2+ , respectively. 65 The small peaks at ∼938 and ∼941 eV were attributed to Cu 2+ satellite peaks.…”

“…Because the binding energy positions between Cu 0 and Cu + are close to each other (only 0.1 eV), the possible presence of Cu was hardly identified. 64 Hence, the Auger spectra of Cu were recorded (Fig. 2(C)).…”

Progress and Future Prospects of Wide‐Bandgap Metal‐Compound‐Based Passivating Contacts for Silicon Solar Cells

“…Surprisingly, the hole selectivity of both NiO x and Cu 2 O was found to be very poor, resulting in inferior device performance. [80][81][82] With a complex Al 2 O 3 /Cu 2 O/Au rear contact, a best PCE of 19.7% was achieved for hybrid p-Si solar cells. [82] In contrast, a polymer-based HSC, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), has been frequently investigated and demonstrated as very effective.…”

“…[80][81][82] With a complex Al 2 O 3 /Cu 2 O/Au rear contact, a best PCE of 19.7% was achieved for hybrid p-Si solar cells. [82] In contrast, a polymer-based HSC, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), has been frequently investigated and demonstrated as very effective. [42,[83][84][85] PEDOT:PSS with various additives was prepared and investigated as a potential HSC, featuring a high conductivity, a high WF, and an acceptable transparency, especially for the rear side.…”

“…However, both of them were proven to show a very poor hole selectivity. [80][81][82] Although the surface passivation of NiO x -and Cu 2 O-based HSCs can be improved with a passivation interlayer, their hole selectivity is mainly limited by a low hole concentration (NiO x : 10 17 to 10 18 cm -3 ; Cu 2 O: 10 14 to 10 16 cm -3 ), [101] preventing the formation of highly asymmetric conductivities for holes and electrons near the surface. Moreover, the valence band maximum (VBM) in these metal oxides, which is the transport path for holes, is made of localized and deep oxygen 2p orbitals, further resulting in poor hole transport.…”