Abstract

Layered transition metal dichalcogenide semiconductors are interesting for photovoltaics owing to their high solar absorbance and efficient carrier diffusion. Tungsten diselenide (WSe₂), in particular, has emerged as a promising solar cell absorber. However, defective metal-semiconductor interfaces have restricted the power conversion efficiency (PCE) to ~6%. Here we report WSe₂ photovoltaics with a record-high PCE of ~11% enabled by ultra-clean indium/gold (In/Au) van der Waals (vdW) contacts. Using grid-patterned top vdW electrodes, we demonstrate near-ideal diodes with a record-high on/off ratio of 1.0×10⁹. Open-circuit voltage (VOC) of 571 ± 9 mV, record-high short-circuit current density (JSC) of 27.19 ± 0.45 mA cm⁻², and fill factor of 69.2 ± 0.7% resulting in PCE of 10.8 ± 0.2% under 1-Sun illumination on large active area (~0.13×0.13 mm2) devices have been realised. The excellent device performance is consistent with the high external quantum efficiency (up to ~93%) measured across a broad spectral range of 500–830 nm.

Abstract

Layered transition metal dichalcogenide semiconductors are interesting for photovoltaics owing to their high solar absorbance and efficient carrier diffusion. Tungsten diselenide (WSe₂), in particular, has emerged as a promising solar cell absorber. However, defective metal-semiconductor interfaces have restricted the power conversion efficiency (PCE) to ~6%. Here we report WSe₂ photovoltaics with a record-high PCE of ~11% enabled by ultra-clean indium/gold (In/Au) van der Waals (vdW) contacts. Using grid-patterned top vdW electrodes, we demonstrate near-ideal diodes with a record-high on/off ratio of 1.0×10⁹. Open-circuit voltage (VOC) of 571 ± 9 mV, record-high short-circuit current density (JSC) of 27.19 ± 0.45 mA cm⁻², and fill factor of 69.2 ± 0.7% resulting in PCE of 10.8 ± 0.2% under 1-Sun illumination on large active area (~0.13×0.13 mm2) devices have been realised. The excellent device performance is consistent with the high external quantum efficiency (up to ~93%) measured across a broad spectral range of 500–830 nm.

Abstract

Layered transition metal dichalcogenide semiconductors are interesting for photovoltaics owing to their high solar absorbance and efficient carrier diffusion. Tungsten diselenide (WSe₂), in particular, has emerged as a promising solar cell absorber. However, defective metal-semiconductor interfaces have restricted the power conversion efficiency (PCE) to ~6%. Here we report WSe₂ photovoltaics with a record-high PCE of ~11% enabled by ultra-clean indium/gold (In/Au) van der Waals (vdW) contacts. Using grid-patterned top vdW electrodes, we demonstrate near-ideal diodes with a record-high on/off ratio of 1.0×10⁹. Open-circuit voltage (VOC) of 571 ± 9 mV, record-high short-circuit current density (JSC) of 27.19 ± 0.45 mA cm⁻², and fill factor of 69.2 ± 0.7% resulting in PCE of 10.8 ± 0.2% under 1-Sun illumination on large active area (~0.13×0.13 mm2) devices have been realised. The excellent device performance is consistent with the high external quantum efficiency (up to ~93%) measured across a broad spectral range of 500–830 nm.

Abstract

Layered transition metal dichalcogenide semiconductors are interesting for photovoltaics owing to their high solar absorbance and efficient carrier diffusion. Tungsten diselenide (WSe₂), in particular, has emerged as a promising solar cell absorber. However, defective metal-semiconductor interfaces have restricted the power conversion efficiency (PCE) to ~6%. Here we report WSe₂ photovoltaics with a record-high PCE of ~11% enabled by ultra-clean indium/gold (In/Au) van der Waals (vdW) contacts. Using grid-patterned top vdW electrodes, we demonstrate near-ideal diodes with a record-high on/off ratio of 1.0×10⁹. Open-circuit voltage (VOC) of 571 ± 9 mV, record-high short-circuit current density (JSC) of 27.19 ± 0.45 mA cm⁻², and fill factor of 69.2 ± 0.7% resulting in PCE of 10.8 ± 0.2% under 1-Sun illumination on large active area (~0.13×0.13 mm2) devices have been realised. The excellent device performance is consistent with the high external quantum efficiency (up to ~93%) measured across a broad spectral range of 500–830 nm.