Influence of the Intermediate Density-of-States Occupancy on Open-Circuit Voltage of Bulk Heterojunction Solar Cells with Different Fullerene Acceptors

García-Belmonte, Germà; Boix, Pablo P.; Bisquert, Juan; Lenes, Martijn; Bolink, Henk J.; Rosa, A. L.; Filippone, Salvatore; Martín, Nazario

doi:10.1021/jz100956d

Cited by 146 publications

(162 citation statements)

References 32 publications

Supporting

Mentioning

149

Contrasting

Unclassified

Order By: Relevance

“…[4][5][6][7] Just like classical thin film solar cells such as, e.g., amorphous silicon, 8,9 these materials are generally disordered, low mobility semiconductors. [10][11][12][13][14][15][16][17] In these materials, disorder creates localized states or traps that have a strong effect on transport and likely also on nonradiative recombination. 10,[18][19][20] Recently, electroluminescence (EL) spectroscopy [21][22][23][24] and imaging 25,26 have been introduced as a novel (for organic semiconductors) characterization tool to study the energy levels as well as recombination and defects in polymer:fullerene solar cells.…”

Section: Introductionmentioning

confidence: 99%

Influence of energetic disorder on electroluminescence emission in polymer:fullerene solar cells

et al. 2012

View full text Add to dashboard Cite

Electroluminescence (EL) spectroscopy and imaging can be useful techniques to analyze various loss mechanisms in solar cells, but the interpretation of the results is not trivial in solar cells made from disordered materials such as organic semiconductors. In this case the interpretation of EL measurements may be affected by the presence of a tail of localized states. Here, we study several polymer:fullerene systems and show that, despite the presence of tail states, the shape of the EL spectrum is insensitive to the applied voltage. This indicates that the emission originates mainly from mobile charges in higher lying states recombining at the polymer:fullerene interface and that most charges in deeper tail states do not contribute to the EL spectrum. The consequence of our finding is that simple models of EL emission in ideal semiconductors can be applied to polymer:fullerene solar cells and can therefore be used to evaluate the potential of different material systems in terms of recombination losses and to study resistive losses using luminescence imaging.

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of energetic disorder on electroluminescence emission in polymer:fullerene solar cells

et al. 2012

View full text Add to dashboard Cite

show abstract

“…[52][53][54] Thus, even in completely defect-free organic solar cells, the inherent disorder in molecular packing and molecular environment should lead to subband-gap states that could contribute to charge-carrier recombination. In the following, we will show how inclusion of exponential tail states occupied by nonmobile or trapped charge carriers and recombination via these states allows us to reproduce experimental data that cannot be reproduced by only assuming free carriers in bands.…”

mentioning

confidence: 99%

Recombination via tail states in polythiophene:fullerene solar cells

et al. 2011

View full text Add to dashboard Cite

State-of-the-art models used for drift-diffusion simulations of organic bulk heterojunction solar cells based on band transport are not capable of reproducing the voltage dependence of dark current density and carrier concentration of such devices, as determined by current-voltage and charge-extraction measurements. Here, we show how to correctly reproduce this experimental data by including an exponential tail of localized states into the density of states for both electrons and holes, and allowing recombination to occur between free charge carriers and charge carriers trapped in these states. When this recombination via tail states is included, the dependence of charge-carrier concentration on voltage is distinctly different from the case of band-to-band recombination and the dependence of recombination current on carrier concentration to a power higher than 2 can be explained.

show abstract

“…The behavior of energy-level alignment at the organic semiconductor/electrode heterointerface leads to the formation of ohmic contact at the cathode side, which is critical for the V oc of PSCs. For the PSCs where ohmic contacts are formed with both electrodes, the V oc is determined by the difference between the HOMO of the donor and the LUMO of the acceptor [43]. On the other hand, the deep VB of ZrIPO leads to formation of a high barrier which blocks the holes from transporting to the cathode efficiently.…”

Section: Resultsmentioning

confidence: 99%

Efficient Polymer Solar Cells with Alcohol-Soluble Zirconium(IV) Isopropoxide Cathode Buffer Layer

Luo

Bai

et al. 2018

Energies

View full text Add to dashboard Cite

Abstract:Interfacial materials are essential to the performance and stability of polymer solar cells (PSCs). Herein, solution-processed zirconium(IV) isopropoxide (Zr[OCH(CH 3 ) 2 ] 4 , ZrIPO) has been employed as an efficient cathode buffer layer between the Al cathode and photoactive layer. The ZrIPO buffer layer is prepared simply via spin-coating its isopropanol solution on the photoactive layer at room temperature without any post-treatment. When using ZrIPO/Al instead of the traditionally used Ca/Al cathode in PSCs, the short-circuit current density (J sc ) is significantly improved and the series resistance of the device is decreased. The power conversion efficiency (PCE) of the P3HT:PCBM-based device with ZrIPO buffer layer reaches 4.47% under the illumination of AM1.5G, 100 mW/cm 2 . A better performance with PCE of 8.07% is achieved when a low bandgap polymer PBDTBDD is selected as donor material. The results indicate that ZrIPO is a promising electron collection material as a substitute of the traditional low-work-function cathode for high performance PSCs.

show abstract

Influence of the Intermediate Density-of-States Occupancy on Open-Circuit Voltage of Bulk Heterojunction Solar Cells with Different Fullerene Acceptors

Cited by 146 publications

References 32 publications

Influence of energetic disorder on electroluminescence emission in polymer:fullerene solar cells

Influence of energetic disorder on electroluminescence emission in polymer:fullerene solar cells

Recombination via tail states in polythiophene:fullerene solar cells

Efficient Polymer Solar Cells with Alcohol-Soluble Zirconium(IV) Isopropoxide Cathode Buffer Layer

Contact Info

Product

Resources

About