A p‐Type Quantum Dot/Organic Donor:Acceptor Solar‐Cell Structure for Extended Spectral Response

Abstract

A coupled PbS quantum dot film and a PSBTBT:PCBM bulk heterojunction layer contribute comparable photocurrent in a new stacked solar‐cell architecture with sensitivity in the near infrared and an efficiency >4%. With a focus on the energy level alignment between components, time‐resolved microwave photoconductivity is used to elucidate the charge transport pathways for electrons and holes.

Near‐Infrared Active Lead Chalcogenide Quantum Dots: Preparation, Post‐Synthesis Ligand Exchange, and Applications in Solar Cells

“…The early QD/polymer solar cells based on lead chalcogenide QDs exhibited an efficiency of 2.2 %. [117] These devices were fabricated based on thin films of 1,3-benzenedithiol (1,3-BDT) crosslinked with PbS QDs that were deposited on C60-fullerene (PCBM) layer to form the planar heterojunction solar cells.. [117] Others have reported bulk heterojunctions of lead chalcogenide QDs with various types of conducting polymers including 1,3-BDT PbS QDs with [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) and achieved an efficiency of 3.7 %, [118] [119] and ethanedithiol (EDT) capped PbSe QDs with PEDOT:PSS as active layers and exhibited the efficiency of 3.4 %. [120] Although many other works have also been reported using lead chalcogenide QDs for QDs/polymer hybrid solar cells, their efficiencies still remain significantly low.…”

Polymer selection toward efficient polymer/PbSe planar heterojunction hybrid solar cells

“…Polymers can offer high absorbance coefficient and excellent film-forming ability while NCs may provide tunable bandgap across visible to near infrared (NIR) and high carrier mobility [1,2]. A variety of inorganic NCs have been studied in HSCs such as cadmium chalcogenides NCs (CdS [3,4], CdSe [5,6], CdTe [7,8]) and lead chalcogenides NCs (PbS [9][10][11], PbSe [12], PbSSe [13]). Compared to cadmium chalcogenides, PbS and PbSe have significant larger exciton Bohr radii (PbS 20 nm, PbSe 46 nm, CdSe 6 nm) [14] and hence demonstrate higher carrier mobility (PbSe 0.9-7 cm À2 V À1 S À1 [15][16][17][18], CdSe $10 À2 cm À2 V À1 S À1 [19]) even without high temperature sintering.…”

Photovoltaic Devices Based on Colloidal PbX Quantum Dots: Progress and Prospects

“…This clever device construction contributed much to the highest reported PCE of 5.5 % . Based on this high maneuverability, PbX QDs were also used to fabricate polymer:PCBM:QDs multicomponent solar cells, QDs/polymer:PCBM and QDs/polymer bilayer structure. It is worth mentioning that PbX QDs can also be pre‐exchanged with short ligand in solution, which will change the surface energy difference between PbX QDs and the polymer and then help to adjust phase separation in the blend film …”