Electrically Reliable Perovskite Photovoltaic Cells Against Instantaneous Kilovolt Stress

Abstract

facilitates the full potential of photovoltaic devices (PVs), whose record efficiency exceeds 29%. [4] In addition, developing the PSCs' roll-to-roll process allows us to fabricate large-area PSCs at low costs. [5] Consequently, PSCs can compete with other PV technologies in the market regarding device performance and manufacturing cost. However, almost all PVs are installed in harsh outdoor conditions where the temperature and humidity vary throughout the year; their reliability also plays a vital role in determining their levelized cost of electricity. Despite the importance of reliability, the inherent poor stability of PSCs makes it difficult for them to fulfill commercialization standards. The short lifetimes of PSCs are mainly attributed to the poor chemical stabilities of the perovskite and buffer layers. Intensive studies have been conducted to prevent perovskite films from reacting with oxygen and moisture, including encapsulation, [6] novel device structures, [7] and buffer engineering. [8] Last of all, several groups suggested general design rules for stable PSCs. [9] Nevertheless, the large-sized, perovskite PV-based energy harvesting system, consisting of parallel and series-connected PSCs, will face other stabilization issues as its size increases to obtain an appropriate voltage and current. Mechanical stress resistance, [10] the fireproofing of PSCs, [11] and stability against electrical stress [12] should be considered. Significantly, the reliability of PSCs against electrical stress becomes a more critical factor because they are supposed to connect a power grid. FromThe electrical stability of perovskite solar cells (PSCs) will play an essential role in their commercialization because field-installed PSCs frequently operate under non-ideal voltages. Particularly, an instantaneous extremely high voltage (IEHVs) from electro-static discharge will be applied to PSCs due to friction in roll-to-roll processes. In addition, lightning strikes and surges from grids are plausible sources of IEHVs to field-installed PSCs. Hence, the effect of IEHVs on PSCs is systematically investigated and a robust device structure is suggested. An IEHV severely deteriorates PSCs by destroying their diode characteristics. Physical and chemical damage from IEHVs to the interface between the perovskite film and buffer layers causes increased recombination losses and series resistance. To reinforce the heterointerface, a well-known surface defect passivation method is adopted, adding excessive PbI 2 to perovskite films. The excessive PbI 2 , mainly located at the interface, successfully protects PSCs from IEHV. Moreover, inserting well-established defect passivation layers, C 60 , and phenethylammonium iodide into the interface of a perovskite film improves the device's stability against IEHV. Therefore, interface defect passivation is viable for stable PSCs against abnormal electrical stress. It is believed that this study will provide fundamental insights for designing electrically reliable PSCs, which is crucial for...

Suppressing Excess Lead Iodide Aggregation and Reducing N‐Type Doping at Perovskite/HTL Interface for Efficient Perovskite Solar Cells

“…[5][6][7][8] In state-of-the-art PSCs, an excess of lead iodide (PbI 2 ) is typically employed to passivate defects, reduce halide vacancies and tune the energy levels of perovskite photoactive layers. [9][10][11][12] However, excess PbI 2 leads to a decrease in the stability of PSCs due to the photodecomposition of PbI 2 , resulting in metallic lead (Pb 0 ) and gaseous I 2 upon exposure to light and heat, which not only increases nonradiative recombination but also degrades device stability. [13,14] In addition, the excess PbI 2 has a low iodine vacancy formation energy, which facilitates ion migration and further initiates perovskite degradation.…”

Abnormal Dynamic Reverse Bias Behavior and Variable Reverse Breakdown Voltage of ETL‐free Perovskite Solar Cells

“…[ 11 ] Although the general stability is constantly improved through various strategies, the reverse bias stability issue has not received sufficient attention yet. [ 5–7,12–14 ]…”

“…[11] Although the general stability is constantly improved through various strategies, the reverse bias stability issue has not received sufficient attention yet. [5][6][7][12][13][14] When the PV modules are working outdoors, some cells are likely to be shaded by snow, tree shade, bird droppings, and black clouds, etc. [15] Next, the shaded cells no longer act as a power output unit, but become a power dissipation diode.…”

Real‐Time Detection and Classification of Bypass Diode‐Related Faults in Photovoltaic Modules via Thermoelectric Devices

“…[18,19] Additionally, lightning strikes and voltage surges might damage the BD and make it lose its diode characteristics. [20,21] Furthermore, the continuous flow of current through BDs, originating from continuous PS, and soiling in PV modules might break them. [22] When BDF occurs, the electrical characteristics of a BD change and become similar to those of a resistor.…”

“…[25][26][27][28] The algorithmbased current-voltage curve analysis enables us to recognize BD errors and faults; however, it does not exactly show which BD is faulty. [21][22][23][24] Furthermore, algorithm-based approaches require additional on-site visits to detect which BD is under errors and faults. Another method for detecting an elevated T BD in large PV power plants involves applying automatic flight drones equipped with thermal cameras.…”