Fullerene-free, MoTe2 atomic layer blended bulk heterojunctions for improved organic solar cell and photodetector performance

Abstract

This paper introduces a facile solution route to fabricate MoTe2 grain nano-domains for hybrid polymer heterojunction solar cells and photodetectors. Fabricated MoTe2 structures were investigated using Raman and XRD, and surface morphologies characterized using FE-SEM and TEM. We subsequently assembled a non-fullerene polymer heterojunction device using the PBDB-T:ITIC active layer for ITO/HTL/active-layer/LiF/Al architype solar cells and photodetectors. We also investigated effects from different MoTe2 nanostructure proportions embedded in the PBDB-T:ITIC polymer matrix as active layers to assemble solar cell and photodetector devices. Maximum power conversion efficiency ≈8.94% with improved carrier mobility ≈9.23 × 10−4 cm2 V−1 s−1 was achieved for 10 vol% MoTe2 nanostructure inclusion with PBDB-T:ITIC active layer. A fabricated photodetector using 10 vol%-MoTe2@PBDB-T:ITIC film achieved maximum detectivity ≈2.62 × 1010 Jones with 0.706 A W−1 responsivity at 755 μW cm−2 light density under 656 nm laser source. The proposed facile approach to fabricate 2D MoTe2 atomic layer infusion with polymer heterojunction offers a credible mechanism to progress interfacial characteristics for future organic semiconducting devices.

Keywords

• Polymer solar cells
• Photodetectors
• MoTe2
• Heterojunction
• TEM