Root-Cause Failure Analysis of Photocurrent Loss in Polythiophene:Fullerene-Based Inverted Solar Cells

Voroshazi, Eszter; Uytterhoeven, Griet; Cnops, Kjell; Conard, Thierry; Favia, P.; Bender, Hugo; Müller, Robert N.; Cheyns, David

doi:10.1021/am506771e

Cited by 29 publications

(21 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is possibly due to the diffusion of Al through the silver, as was reported recently in a different study. [ 45 ] In the dark tests, devices with PEDOT:PSS appear more frequently, yet they signifi cantly underperform compared to the PEDOT:PSS-free samples. In addition, the majority of the dark tests have winning samples that utilize Ag or Au instead of Al.…”

Section: Role Of the Photoactive Layermentioning

confidence: 95%

“…It is important to note that the samples where the top Al electrode is directly applied onto the PAL show similar lifetimes under illumination independent of whether the device is encapsulated or not ( Figure 5 b,d). This suggests that, despite the elimination of oxygen and water, the Al/PAL interface remains detrimental to the performance of the device [ 45 ] The results of the device geometry analysis suggest that when considering real operational (outdoor) conditions in an environment with the presence of humidity, oxygen and light, both normal (Al) and inverted (Ag or Au) structures are prone to rapid degradation when unprotected, but can perform equally well when encapsulated.…”

Section: Device Geometry: Normal Versus Invertedmentioning

confidence: 99%

See 1 more Smart Citation

Lifetime of Organic Photovoltaics: Status and Predictions

Gevorgyan

Madsen

Roth

et al. 2015

Advanced Energy Materials

137

124

View full text Add to dashboard Cite

performance level, especially when considering large-scale mass-produced modules, is predicted to be signifi cantly lower. [ 8 ] Nevertheless, based on recent advances in the upscaling of OPV manufacture [9][10][11][12] it is reasonable to assume that the mass production of modules with an effi ciency of more than 5% is an achievable target today. Durability of OPV is however yet to be proven and demonstrated.Due to core architectural differences between OPV and inorganic technologies [ 13 ] the established testing standards of the latter are not applicable to the former. [ 1 ] Hence, for many years the stability testing of OPV has primarily been based on customized procedures that vary from one laboratory to another, generating incomparable data. [ 14 ] Moreover, due to the complexity of the OPV device architectures [ 15 ] and a multitude of aging mechanisms taking place at the same time [ 16 ] the aging curve of OPV often takes a complex shape, which is diffi cult to model, [ 14,17 ] thus making the identifi cation of a practical operational lifetime diffi cult or impossible. [ 18 ] As a result, even with a multitude of reported review articles discussing OPV stability [ 16,[19][20][21][22][23][24] at hand, it is still challenging to identify where the technology stands in terms of lifetime. To address this it is necessary to create a yardstick -a generic marker that allows accurate rating and comparison of the lifetime for OPV, and thus enabling the gauging of progress over time. An additional complication that has arisen due to the signifi cant improvements in OPV stability and durability in recent years is that the determination of OPV lifetimes has become an impractically long process, and establishing markers for both accelerated and real operational test conditions (if successful) would allow developing a prediction tool that could speed up the stability testing process and tackle this issue.The groundwork towards creating such a marker was laid in 2011 at the International Summit on OPV Stability (ISOS) where the ISOS testing guidelines were decided upon and described for OPV technologies. [ 18 ] These guidelines were primarily aimed at harmonizing testing procedures among different laboratories by offering a set of indoor and outdoor tests with controlled conditions. This has helped to reduce variations in the reported results, making the aging studies of different laboratories more comparable. [ 25 ] While the ISOS tests harmonized the test conditions, the questions of how to generically determine the lifetime from aging curves of diverse shapes, and how to build a technique for predicting the lifetime based on accelerated tests remained.The results of a meta-analysis conducted on organic photovoltaics (OPV) lifetime data reported in the literature is presented through the compilation of an extensive OPV lifetime database based on a large number of articles, followed by analysis of the large body of data. We fully reveal the progress of reported OPV lifetimes. Furthermore, a generic lifetime marker has...

show abstract

Section: Role Of the Photoactive Layermentioning

confidence: 95%

Section: Device Geometry: Normal Versus Invertedmentioning

confidence: 99%

Lifetime of Organic Photovoltaics: Status and Predictions

Gevorgyan

Madsen

Roth

et al. 2015

Advanced Energy Materials

137

124

View full text Add to dashboard Cite

show abstract

“…Griffin et al have reported that molybdenum oxide releases oxygen under heating, leading to lower molybdenum oxidation states and a shift in the work function. Other authors have shown that molybdenum oxide can negatively interact with the metal anode, thus leading to reduced stability even without illumination …”

Section: Resultsmentioning

confidence: 99%

Solution‐Processable Anode Double Buffer Layers for Inverted Polymer Solar Cells

Cominetti

Serrano

Savoini

et al. 2020

Physica Status Solidi (a)

View full text Add to dashboard Cite

Although organic solar cells have surpassed the 17% power conversion efficiency threshold, commercial modules efficiencies are only around 4–5%. One of the reason is the lack of effective solution‐processable hole transport materials that are a key element for the scale‐up on roll‐to‐roll printing equipments and the commercial development. Herein, a class of novel vanadium and molybdenum polyoxometallate salts are developed that, alone or in combination with a traditional poly(ethylene‐3,4‐dioxytiophene):poly(styrene sulfonate) (PEDOT:PSS) layer, can be used as anodic buffer layer in inverted polymer solar cells. These materials exhibit work function values around 5.8 eV that match well with highest occupied molecular orbital energies of typical polymer donors. They are tested with different widely used active systems, including PTB7:PC71BM, PV2000:PCBM, and PffBT4T:PC71BM. Vanadium and molybdenum polyoxometallate can be deposited from solutions and, contrary to PEDOT:PSS used alone, do not cause a drop of performances compared with evaporated molybdenum oxide (e‐MoOx); on the contrary, in the best cases they achieve similar performances to e‐MoOx. Slot‐die‐coated PV2000:PCBM solar cells on flexible substrate achieve a remarkable power conversion efficiency of almost 7.6%.

show abstract

“…27 Another aspect of the degradation mechanism of inverted OPVs with the aforementioned top electrode was pointed out by Rösch et al through different imaging techniques, whereby they attributed the failure to the migration of silver and diffusion into the MoO 3 layer, changing its work function. 28 Greenbank et al also discuss diffusion into the active layer, and its resulting weakening is correlated to the decline (specifically J sc reduction) in the device performance when used in conjunction with MoO 3 as the HTL.…”

Section: Introductionmentioning

confidence: 98%

Influence of the Hole Transporting Layer on the Thermal Stability of Inverted Organic Photovoltaics Using Accelerated-Heat Lifetime Protocols

Hermerschmidt

Savva

Georgiou

et al. 2017

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

High power conversion efficiency (PCE) inverted organic photovoltaics (OPVs) usually use thermally evaporated MoO3 as a hole transporting layer (HTL). Despite the high PCE values reported, stability investigations are still limited and the exact degradation mechanisms of inverted OPVs using thermally evaporated MoO3 HTL remain unclear under different environmental stress factors. In this study, we monitor the accelerated lifetime performance under the ISOS-D-2 protocol (heat conditions 65 °C) of nonencapsulated inverted OPVs based on the thiophene-based active layer materials poly(3-hexylthiophene) (P3HT), poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7), and thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTTT) blended with [6,6]-phenyl C71-butyric acid methyl ester (PC[70]BM). The presented investigation of degradation mechanisms focus on optimized P3HT:PC[70]BM-based inverted OPVs. Specifically, we present a systematic study on the thermal stability of inverted P3HT:PC[70]BM OPVs using solution-processed poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and evaporated MoO3 HTL. Using a series of measurements and reverse engineering methods, we report that the P3HT:PC[70]BM/MoO3 interface is the main origin of failure of the P3HT:PC[70]BM-based inverted OPVs under intense heat conditions, a trend that is also observed for the other two thiophene-based polymers used in this study.

show abstract

Root-Cause Failure Analysis of Photocurrent Loss in Polythiophene:Fullerene-Based Inverted Solar Cells

Cited by 29 publications

References 27 publications

Lifetime of Organic Photovoltaics: Status and Predictions

Lifetime of Organic Photovoltaics: Status and Predictions

Solution‐Processable Anode Double Buffer Layers for Inverted Polymer Solar Cells

Influence of the Hole Transporting Layer on the Thermal Stability of Inverted Organic Photovoltaics Using Accelerated-Heat Lifetime Protocols

Contact Info

Product

Resources

About