CELIV to estimate the Charge Carrier Mobility in Perovskite Solar Cells
/One of the main parameters determining the efficiency of a solar cell is the mobility of the charge carriers.
So how do we determine the carrier mobility in a thin-film solar cell?
A frequently used technique is the Charge Extraction by Linearly Increasing Voltage (CELIV).
In this Episode 3 of our Fluxim’s Science Shorts, Dr. Antonio Cabas Vidani explains how to perform these measurements with an unexpected discovery. Click play below to learn more about this technique.
WCPE-8 - The World Conference on Photovoltaic Energy Conversion
26 – 30 September 2022 in the Milano Convention Centre in Milan, Italy
We are very happy to be exhibiting and presenting at this highly anticipated conference which brings together the three largest and most prominent international PV conferences: the European PV Solar Energy Conference (39th EU PVSEC), the Photovoltaic Specialists Conference (IEEE PVSC-51), and the International PV Science and Engineering Conference (PVSEC-32).
We are sending three of our finest minds who will be manning our booth so if you are attending please stop by Stand A11 (next to the coffee zone) and they will be happy to discuss (in English/Korean/Italian/German/French or Swiss German) your research and if Fluxim’s tools and expertise can help boost it!
Our colleague Simon Zeder will also be making a presentation on the following topic:
The Role of Reabsorption in Pero/Si Tandems Assessed by Optoelectronic Simulation
Session Code: 2BO.8
Room: Main Auditorium Red
Date: 27 September 2022 13:30 - 15:00
Our colleague from Ennio Comi from the ZHAW School of Engineering will also be with us and presenting:
Electro-thermal Model for Lock-in Infrared Imaging of Defects in Perovskite Solar Cells
Session Code: 2BO.8
Room: Main Auditorium Red
Date: 27 September 2022 13:30 - 15:00
The full WCPEC-8 program can be accessed here
More Exciting Results from our Customers
Heterogeneous Integration of Colloidal Quantum Dot Inks on Silicon Enables Highly Efficient and Stable Infrared Photodetectors
Qiwei Xu, I. Teng Cheong, Hanfa Song, Vien Van, Jonathan G. C. Veinot, and Xihua Wang
ACS Photonics (2022), 9, 8, 2792–2801
doi/pdf/10.1021/acsphotonics.2c00587
Integrating lead sulfide (PbS) colloidal quantum dots (CQDs) with crystalline silicon (c-Si) has been proven to be an effective strategy in extending the sensitivity of Si-based photodetectors into the infrared (IR).
Here, the team demonstrates the successful integration of PbS CQD inks with Si and the fabrication of an efficient heterojunction IR photodiode operating in the range of 800 - 1500 nm.
Main Results:
PbS CQD on Si to increase the sensitivity of Si to IR
CQD:Si photodetector operating from 800 to 1500 nm
A layer of p-type QD enhances the built-in electric field
EQE of 44% at 1280nm and 2V reverse bias - stable for more than 600 h
Photoresponse lower than 4μs without tails, which indicates low trap density
Lead sulfide (PbS) colloidal quantum dots (CQD) enable Si photodetector sensitivity in the near-infrared (NIR) from 800 to 1500 nm.
With Transient Photocurrent (TPC) and Transient Photovoltage (TPV), they demonstrated that there is low trap density at the CQD:Si interface. TPC and TPV measurements were performed with the all-in-one characterization platform PAIOS from Fluxim AG.
Organic Solar Cell With Efficiency Over 20% and VOC Exceeding 2.1 V Enabled by Tandem With All-Inorganic Perovskite and Thermal Annealing-Free Process
Xiaoyu Gu, Xue Lai, Yuniu Zhang, Teng Wang, Wen Liang Tan, Christopher R. McNeill, Qian Liu, Prashant Sonar, Feng He, Wenhui Li, Chengwei Shan, and Aung Ko Ko Kyaw
Adv. Sci. (2022), 2200445, 1.
doi/pdf/10.1002/advs.202200445
Organic solar cells (OSCs) based on polymer donor and non-fullerene acceptor achieve power conversion efficiency (PCE) of more than 19%. However, their poor absorption below 550 nm restricts the harvesting of high-energy photons. In contrast, wide bandgap all-inorganic perovskites limit the absorption of low-energy photons and cause serious below bandgap losses.
The authors are proposing a 2-terminal (2T) monolithic perovskite/organic tandem solar cell (TSC) incorporating wide bandgap CsPbI2Br as front cell absorber and organic PM6:Y6 blend as rear cell absorber. This combination extends the absorption of their OSCs into the high-energy photon regime.
Main Results:
1mV difference between the Voc of an organic-perovskite tandem solar cell and the sum of the individual sub-cells.
TA vs TA-free to optimize Voc loss in OSC (CV, EIS).
PCE = 20.6% in a small-area device. PCE = 16.5% in large-area solar cells.
High Voc. The champion device has a Voc loss of 0.001 V (almost perfect ICL).
The devices are stable during a 700h-stressing in N2.
This remarkable result was obtained by the group of Aung Ko Ko Kyaw at Guangdong University. The team determined also that thermal annealing (TA) creates a barrier at the ICL (electrode/PFN-Br interface). This must be avoided for efficient charge transport between the subcells.
Capacitance and impedance measurements were performed with Paios.
Tailoring the Nature of Interface States in Efficient and Stable Bilayer Organic Solar Cells by a Transfer-Printing Technique
Rong Wang, Youyu Jiang, Wolfgang Gruber, Yakun He, Mingjian Wu, Paul Weitz, Kaicheng Zhang, Larry Lüer, Karen Forberich, Tobias Unruh, Erdmann Spiecker, Carsten Deibel, Ning Li,* and Christoph J. Brabec
Adv. Mater. Interfaces (2022), 9, 2200342
https://onlinelibrary.wiley.com/doi/full/10.1002/admi.202200342
Now, there are bilayer organic solar cells (BL-OSCs) that perform like bulk-heterojunctions (BHJ-OSCs), but with longer stability. This is possible by orienting the polymer donor (PM6) with DIO-additive.
This was a recent finding from the group of Prof. Christoph Brabec at the i-MEET. The researchers developed an innovative dry-transfer deposition method called spreading transfer printing (STP). The ordering of PM6 on the BL-OSC resulted in a higher Voc, higher Jsc, and reduced charge recombination compared to the BHJ.
A drift-diffusion simulation with the software Setfos from FLUXiM AG combined with the experiments, allowed them to determine the impact of the charge orientation on charge generation and device efficiency.
High performance polymerized small molecule acceptor by synergistic optimization on π-bridge linker and side chain
Sun, G., Jiang, X., Li, X. et al.
https://doi.org/10.1038/s41467-022-32964-z
It’s not just perovskite solar cells making headlines. All-polymer solar cells (PSCs) have now efficiency of almost 18%.
Polymeric small molecule acceptors (PSMAs) are narrow bandgap small-molecule acceptors (SMAs) copolymerized with a π-bridge linking unit (linker). A power conversion efficiency of 17.24% was recently achieved by the group of Yongfang Li at the Beijing National Laboratory of Molecular Sciences by testing three PY-IT derivatives. PG-IT2F was the champion polymer with lower recombination and improved charge transport.
With PAIOS they performed light-dependent transient photovoltage (TPV) measurements and estimated a charge-carrier lifetime of 0.769 us for the PG-IT2F solar cell compared to 0.436 us for the PY-IT reference device.
