Improved Performance and Stability in Quantum Dot Solar Cells through Band Alignment Engineering


QDOT images 6

Published online: 25 May 2014

Solution processing is a promising route for the realization of low-cost, large-area, flexible and lightweight photovoltaic devices with short energy payback time and high specific power.

 

 

 

However, solar cells based on solution-processed organic, inorganic and hybrid materials reported thus far generally suffer from poor air stability, require an inert-atmosphere processing environment or necessitate high-temperature processing1, all of which increase manufacturing complexities and costs.

Simultaneously fulfilling the goals of high efficiency, low-temperature fabrication conditions and good atmospheric stability remains a major technical challenge, which may be addressed, as we demonstrate here, with the development of room-temperature solution-processed ZnO/PbS quantum dot solar cells.

By engineering the band alignment of the quantum dot layers through the use of different ligand treatments, a certified efficiency of 8.55% has been reached.

Furthermore, the performance of unencapsulated devices remains unchanged for over 150 days of storage in air. This material system introduces a new approach towards the goal of high-performance air-stable solar cells compatible with simple solution processes and deposition on flexible substrates.

 

At a glance

nmat3984-f1

a, Device architectures. b, Representative J–V characteristics of devices with Au anodes under simulated AM1.5G irradiation (100 mW cm−2). The PbS-TBAI device consists of 12 layers of PbS-TBAI and the PbS-TBAI/PbS-EDT device consists o…

nmat3984-f2

a, Energy levels with respect to vacuum for pure PbS-TBAI, pure PbS-EDT and PbS-TBAI films covered with different thicknesses of PbS-EDT layers. The Fermi levels (EF, dashed line) and valence band edges (EV, blue lines) were determined

nmat3984-f3

a, Open circuit voltage (VOC). b, Short-circuit current (JSC). c, Fill factor (FF). d, Power conversion efficiency (PCE). Measurements were performed in a nitrogen-filled glovebox. Day 0 denotes measurements performed after anode evapo…

nmat3984-f4

a, Evolution of photovoltaic parameters of PbS-TBAI (black) and PbS-TBAI/PbS-EDT (red) devices. Open symbols represent the average values and solid symbols represent the values for the best-performing device. b, Device performance of a…

Chia-Hao M. Chuang,1,

Journal name: Nature Materials: Year published: (2014)
DOI: doi:10.1038/nmat3984
Received: 06 December 2013
Accepted: 15 April 2014

 

 

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