Perovskite (MaPbI3) Aging Signal in Millimeter Wave Transients

Hybrid organic-inorganic perovskite (HOIP) exhibit low cost, versatility in fabrication methods and possess good application potential because of high power conversion efficiency. Methylammonium lead Iodide (MAPbI3) with quartz substrate thin film sample (glass encapsulated) was obtained from NC State University have been used to obtain millimeter wave (mmw) transient response at probe frequencies of 140 and 150 GHz from CIDO and BWO sources respectively. The HOIP film was produced at NC State University on May 02, 2017. In our time-resolved TR-mmWC apparatus, the glass-covered sample was excited by a 1KHz triggered 532 nm laser beam with a width of 0.7 ns with maximum fluence 10 microJoules per sq. cm and a spot size of 10mm. Transient datasets were recorded using a 6 GHz input bandwidth digitizer after amplifying Schottky detector registered radiofrequency (RF) signal due to differential absorption of the passing millimeter wave from source (normal to sample) at 140 and 150 GHz through sample. Signal averaging was done 4096 times and data were collected on 4 different dates spanning 2, 6, and 8 months and 1 year from date of manufacture. Data attached here represent the complete set of aging signals collected over 0 to about 40,000 hours after production of the MAPbI3 thin film in 2017. Dataset comprises of 120 GHz and 150 GHz probe. Generally, an increase in radiative and trap-assisted recombination lifetimes of charge carriers was noted, and a decrease in amplitudes were also noted after fitting data by double exponential. The fits are obtained by adding a second excitation to account for double peaks. Data attached are CSV files with column 1 being the pump-probe delay time (second), and column 2 being voltage response (V). The low noise amplifier gain of 15.527 dB must be accounted for June 28, 2017, December 18, 2017, and February 21, 2018 datasets and a gain of 15.91 dB must be accounted for the data file obtained on May 03, 2018 to yield the actual voltages. Examples: File with name “NCSU-Perovskite-CIDO-6-140GHz-3-26-RF-Average-FullLaserPower-June-28-2017” is obtained using a solid state IMPATT cavity oscillator operated at 140 GHz with 10 mW output power and after illuminating the sample with full laser power (22.14 mW). Filename: “NCSU-Perovskite-BWO-150GHz-1KHz-FullLaserPower-Dec-18-2017” is the average transient for the same sample obtained on December 18, 2017 but using an electrovacuum BWO as probe source that is operated at 30% power level to transmit the same output power ~ 10 mW and further use of only about 0.32 mW for probing (in all cases using a beam splitter). A code to handle the data, compute, and plot the trends of step responses of the 120- and 150 GHz combined set for GPR based machine learning is added in this repository (Note: some filenames in the code need to be adjusted with the additional extension added in order to avoid repeating names, and directory structure need to be modified)杂化有机-无机钙钛矿（Hybrid organic-inorganic perovskite, HOIP）具备制备成本低廉、制备方法灵活多样的优势，且凭借较高的功率转换效率展现出优异的应用潜力。本研究所用的石英衬底玻璃封装甲胺铅碘（Methylammonium lead Iodide, MAPbI₃）薄膜样品由北卡罗来纳州立大学（NC State University）提供，我们分别利用CIDO源与BWO源，在140 GHz与150 GHz的探测频率下获取了其毫米波（millimeter wave, mmW）瞬态响应数据。该HOIP薄膜于2017年5月2日在北卡罗来纳州立大学制备完成。在本研究的时间分辨毫米波瞬态（TR-mmWC）测试装置中，我们采用脉宽0.7 ns、最大能量注量为10 μJ/cm²、光斑尺寸为10 mm的1 kHz触发532 nm激光束对覆玻璃样品进行泵浦激发。在对肖特基探测器（Schottky detector）采集到的射频（radiofrequency, RF）信号进行放大后，我们通过输入带宽为6 GHz的数字化仪记录了瞬态数据集；该RF信号源于样品对垂直入射的140 GHz与150 GHz毫米波的差分吸收。我们对信号进行了4096次平均处理，并在样品制备后的2个月、6个月、8个月以及1年这4个不同时间节点完成了数据采集。本次附带的数据集完整涵盖了2017年该MAPbI₃薄膜制备后0至约40000小时内的老化信号，包含120 GHz与150 GHz两种探测频率的测试数据。通过双指数拟合对数据进行分析后，我们观察到载流子的辐射复合寿命与陷阱辅助复合寿命均呈现上升趋势，而信号幅值则出现下降。拟合过程中通过引入二次激发项以拟合双峰值特征。本次附带的数据均为CSV格式文件，其中第1列为泵浦探测延迟时间（单位：秒），第2列为电压响应值（单位：伏特）。2017年6月28日、2017年12月18日与2018年2月21日的数据集需补偿15.527 dB的低噪声放大器增益，而2018年5月3日的数据集需补偿15.91 dB的低噪声放大器增益，方可得到真实的电压值。示例1：名为"NCSU-Perovskite-CIDO-6-140GHz-3-26-RF-Average-FullLaserPower-June-28-2017"的文件，采用工作于140 GHz、输出功率10 mW的固态碰撞电离雪崩渡越时间（IMPATT）腔振荡器作为探测源，并以全功率（22.14 mW）的激光照射样品得到。示例2：文件"NCSU-Perovskite-BWO-150GHz-1KHz-FullLaserPower-Dec-18-2017"为2017年12月18日获取的同一样品的平均瞬态响应数据，其采用工作于30%功率档位的电真空返波管（Backward Wave Oscillator, BWO）作为探测源，以获得约10 mW的输出功率，且仅利用约0.32 mW的功率进行探测（所有测试均通过分束器实现）。本代码仓库中附带了用于处理数据、计算并绘制120 GHz与150 GHz联合数据集阶跃响应趋势的代码，可用于基于探地雷达（Ground Penetrating Radar, GPR）的机器学习任务（注：部分文件名需添加额外扩展名以避免重名，同时需调整目录结构）