High-performance parallel tandem MoTe2/perovskite solar cell based on reduced graphene oxide as hole transport layer

Abstract

Abstract Recently, the impressive achievements accomplished in multijunction (tandem) perovskite solar cells have triggered a huge research effort to boost their performance. Here, using a three-dimensional (3D) finite element method (FEM) technique, we propose and investigate a parallel tandem PSCs consisting of two absorbing layers of MoTe 2 and CH 3 NH 3 PbI 3 with cascaded bandgaps to more efficiently use the near-infrared (NIR) solar spectrum. Endowed with a bandgap of about 1 eV, the MoTe 2 layer in conjunction with a CH 3 NH 3 PbI 3 layer is able to broaden the light absorption range of structure beyond the wavelength of 800 nm, up to 1200 nm. In addition to this, the MoTe 2 material can not only appreciably harvest light even with a thickness as low as 20 nm due to their high absorption coefficient, but also make a perfect band alignment with the CH 3 NH 3 PbI 3 layer. As a result, the proposed multijunction PCS yields a high power conversion efficiency (PCE) of 18.52% with a V OC of 0.83 V, J sc of 26.25 mA/cm 2 , and FF of 0.84, which is considerably greater than its corresponding single-junction PSCs with PCE, V OC , J sc , and FF of, 14.01%, 1.14 V, 15.20 mA/cm 2 , and 0.81, respectively. Furthermore, to mitigate the V OC loss caused by the low bandgap of MoTe 2 , we demonstrate an increase in V OC from 0.84 to 0.928 V and in PCE from 18.52% to 20.32%, when we replace a reduced graphene oxide (rGO) layer with Spiro-OMeTAD layer as a hole transport layer (HTL).

Topics & Concepts