Advances in Synthesis and Integration Methods for Enhanced Properties, and Applications in Emerging Nanomaterials: Energy Materials I: Energy Storage Materials and Hybrid Perovskite Solar Cells
Sponsored by: TMS: Nanomaterials Committee
Program Organizers: Chang-Yong Nam, Brookhaven National Laboratory; Jung-Kun Lee, University of Pittsburgh; Zubaer Hossain, University of Delaware
Tuesday 2:00 PM
November 3, 2020
Room: Virtual Meeting Room 25
Location: MS&T Virtual
Session Chair: Zubaer Hossain, University of Delaware
2:00 PM Invited
Polymer Additives for Stable Hybrid Perovskite Solar Cells: Chang-Yong Nam1; 1Brookhaven National Laboratory
In this talk, I will discuss a new linear polar polymer additive, polycaprolactone (PCL), that can functionalize grain boundaries (GBs) in methylammonium lead triiodie (MAPbI3) hybrid perovskites via direct backbone attachment, enabling significantly enhanced perovskite solar cell (PSC) performance and environmental stability. The champion PSC with optimal PCL concentration shows a power conversion efficiency (PCE) of 20.1%, which is reduced by only 10% after 400-h, ambient air storage. 500-h continuous thermal aging at 85 °C still preserves ~65% of the initial PCE. The PCL GB passivation is visualized directly via lateral scanning force and transmission electron microscopies, supporting the roles of PCL in suppressing moisture ingression and ion migration. Secondary ion mass spectrometry and ion conduction measurements confirm the PCL GB functionalization significantly retards I- ion migration in MAPbI3 PSCs while without PCL, I- ions spontaneously accumulate at the organic hole transport layer interface even without externally applied electric field.
2:30 PM Invited
Nanoscale Oxide Layers for Halide Perovskite Solar Cells: Jung-Kun Lee1; Seongha Lee1; Fen Qin1; Matthew Duff1; 1University of Pittsburgh
In this presentation, I will introduce on-going research to apply the nanoscale oxide layers to perovskite solar cells (PSCs) as the carrier transport layer or the conducting transparent oxide layer. The first part of the presentation will be focused on flexible solar cells using inorganic-organic halide perovskite light absorber. Our results show that the thermally oxidized Ni film can be an excellent hole transport layer of PSCs and the residual stress in NiO film is an important parameter to control the carrier recombination of PSCs. In the second part, a design rule of multi-functional transparent electrode for stable and efficient PSCs will be presented. By combining experimental and theoretical methods, we have explored transparent and conducting dielectric/metal/dielectric multilayers. This multilayer is not only a good transparent electrode but also a good passivation layer to suppress the photodegradation of PSCs.