| Work Detail |
A team of German researchers claims to have achieved the highest open-circuit voltage recorded to date in a perovskite solar cell based on hybrid lead methylamine chloride (MAPbCl3). The novel perovskite absorber was fabricated using a two-step deposition method and annealing under molecular nitrogen (N2) gas inside a glove box.
Researchers at Germanys University of Stuttgart have fabricated a transparent single-junction perovskite solar cell based on hybrid methylamine lead chloride (MAPbCl3), a perovskite material with one of the largest energy band gaps among all perovskites.
“Our new cell opens the door to wide bandgap perovskite solar cells, which will be crucial not only for applications such as the Internet of Things (IoT) or solar windows, but also for multijunction solar cells,” said the corresponding author of the investigation, Michael Saliba, to pv magazine . “Single junction perovskites with wide bandgaps have not yet reached high voltages.”
The scientists explained that the application of this material in solar cells is limited by the rapid crystallization kinetics and the poor solubility of its precursors, which results in incomplete coverage of the film with an irregular morphology.
To overcome this problem, the research group adopted a two-step deposition method and annealing under molecular nitrogen (N2) gas inside a glove box. “We demonstrate that the annealing atmosphere greatly influences the crystallization kinetics of MAPbCl3 without modifying its properties,” says Mahdi Malekshahi, co-author of the work. “During annealing in a N2 atmosphere, MAPbCl3 films have poor surface coverage, with many voids and a high root mean square (RMS) of about 64 nm.”
The academics built the cell with a fluorine-doped tin oxide (FTO) substrate, a carbon dioxide-titanium (C/TiO2)-based electron transport layer (ETL), a mesoporous TiO2 layer, the MAPbCl3 absorber , a Spiro-OMeTAD hole transport layer (HTL) and a gold (Au) metal contact.
Tested under standard lighting conditions, the device achieved a power conversion efficiency of 0.81%, an open circuit voltage of 1.71 V, a short circuit current density of 0.73 mA cm-2, and a 64.7% filling.
“It is noteworthy that such a high open-circuit voltage of 1.78 V was obtained for a wide bandgap perovskite using a conventional spiro-OMeTAD HTL,” the researchers noted, indicating that the open-circuit voltage is the highest recorded to date for a MAPbCl3-based perovskite solar cell.
“More importantly, this is achieved with the same contacts used for perovskite solar cells with narrow bandgaps that have broken the world record for efficiency,” added Saliba. “Surprisingly, the conventional spiro-OMeTAD hole transport layer, optimized for narrow bandgaps, supports such high voltages.”
The solar cell concept is described in the article “ MAPbCl3 Light Absorber for Highest Voltage Perovskite Solar Cells ,” recently published in ACS Publications . |
