Abstract
In this work, we examine the impact of hybrid bimetallic Au/Ag core/shell nanostructures on the carrier dynamics of methylammonium lead tribromide (MAPbBr3) mesoporous perovskite solar cells (PSCs). Plasmon-enhanced PSCs incorporated with Au/Ag nanostructures demonstrated improved light harvesting and increased power conversion efficiency by 26% relative to reference devices. Two complementary spectral techniques, transient absorption spectroscopy (TAS) and time-resolved photoluminescence (trPL), were employed to gain a mechanistic understanding of plasmonic enhancement processes. TAS revealed a decrease in the photobleach formation time, which suggests that the nanostructures improve hot carrier thermalization to an equilibrium distribution, relieving hot phonon bottleneck in MAPbBr3 perovskites. TAS also showed a decrease in carrier decay lifetimes, indicating that nanostructures enhance photoinduced carrier generation and promote efficient electron injection into TiO2 prior to bulk recombination. Furthermore, nanostructure-incorporated perovskite films demonstrated quenching in steady-state PL and decreases in trPL carrier lifetimes, providing further evidence of improved carrier injection in plasmon-enhanced mesoporous PSCs.
| Original language | English |
|---|---|
| Pages (from-to) | 1475-1483 |
| Number of pages | 9 |
| Journal | Nanoscale |
| Volume | 9 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jan 28 2017 |
Funding
HFZ acknowledges support from Vanderbilt University Discovery grant, NSF EPSCOR (NSF EPS1004083), NSF BRIGE (EEC 1342185), and the Department of Education for Graduate Assistance in Areas of National Need (GAANN) Fellowship under grant number P0200A090323. EMT acknowledges the VINSE fellowship and Vanderbilt start-up funds. TEM images were obtained with an instrument supported by NSF EPS 1004083. Ultrafast and photoluminescence measurements were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.