Direct Plasmonic Solar Cell Efficiency Dependence on Spiro-OMeTAD Li-TFSI Content.

Xinjian Geng,Mohamed Abdellah,Jacinto Sá,Matilda Folkenant,Tomas Edvinsson,Robert Bericat Vadell

doi:10.3390/nano11123329

Abstract

The proliferation of the internet of things (IoT) and other low-power devices demands the development of energy harvesting solutions to alleviate IoT hardware dependence on single-use batteries, making their deployment more sustainable. The propagation of energy harvesting solutions is strongly associated with technical performance, cost and aesthetics, with the latter often being the driver of adoption. The general abundance of light in the vicinity of IoT devices under their main operation window enables the use of indoor and outdoor photovoltaics as energy harvesters. From those, highly transparent solar cells allow an increased possibility to place a sustainable power source close to the sensors without significant visual appearance. Herein, we report the effect of hole transport layer Li-TFSI dopant content on semi-transparent, direct plasmonic solar cells (DPSC) with a transparency of more than 80% in the 450–800 nm region. The findings revealed that the amount of oxidized spiro-OMeTAD (spiro+TFSI−) significantly modulates the transparency, effective conductance and conditions of device performance, with an optimal performance reached at around 33% relative concentration of Li-TFSI concerning spiro-OMeTAD. The Li-TFSI content did not affect the immediate charge extraction, as revealed by an analysis of electron–phonon lifetime. Hot electrons and holes were injected into the respective layers within 150 fs, suggesting simultaneous injection, as supported by the absence of hysteresis in the I–V curves. The spiro-OMeTAD layer reduces the Au nanoparticles’ reflection/backscattering, which improves the overall cell transparency. The results show that the system can be made highly transparent by precise tuning of the doping level of the spiro-OMeTAD layer with retained plasmonics, large optical cross-sections and the ultrathin nature of the devices.

Highlights

direct plasmonic solar cells (DPSC) architecture resembles organic and perovskite photovoltaic cell structures consisting of active material, in this case, plasmonic nanoparticles, sandwiched between electron- and hole-transporting materials
Another important observation is that the addition of spiro-OMeTAD did not affect the rising edge component, which is better observed in Figure 6b; this observation suggests that holes are injected within 150 fs, similar to hot electrons
(spiro findings revealed that the amount of oxidized spiro-OMeTAD significantly conditioned device performance

Summary

Introduction

DPSC architecture resembles organic and perovskite photovoltaic cell structures consisting of active material, in this case, plasmonic nanoparticles, sandwiched between electron- and hole-transporting materials. A later report showed that quantum efficiency depends on parti of 14 cle size, with smaller sizes showing higher efficiencies [23] Note that in both studies the authors used spiro-OMeTAD without tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III) tri[bis(trifluoromethane)sulfonimide (FK209), making the material colorless and more but less efficient, to studies on perovskites solar cells [24,25]. Studies were notgroup performed on photovoltaic plasmonic hot electrons and holes can be injected into specific accepting layers individually architectures that have been proven to work. The Li-TFSI contents regulated amount of oxidized spiro-OMeTAD species, that hot holes and electrons were injectedthe concomitantly and, no hysteresis which was the central controller of device performance. With performances that showed it to be adequate for use as an energy harvester to power devices, as IoT sensors and e-paper displays

Materials and Methods

3.3.Results

Findings

TIRAS measurements charge injection forondevice containing spiro-OMeTAD

Conclusions