01. The powerful real-time measurement and analysis for PV parameters

Date: Feb. 8, 2021

KA6000 – The Most Comprehensive IV Measurement and Analysis Software for Perovskite Solar Cells.  

01. The powerful real-time measurement and analysis for PV parameters  

With over 10 years of experience, IVS-KA6000 PV Test IV software has been developed by Enli Technology. IVS-KA6000 can control a variety of SMUs and perform data collection of current and voltage based on setting parameters by users. The formulas and algorithms of IVS-KA6000 are based on the foundation developed and released by NREL. 

The powerful features and functions of IVS-KA6000 will be introduced in the following series of articles. Users can clearly understand how to improve the efficiency in solar cell research by IVS-KA6000. Besides, IVS-KA6000 software has assisted many customers to continuously break through the record of the highest cell-conversion-efficiency and published on NREL’s best cell efficiency chart. For example, 23.3% perovskite solar cells of the Chinese Academy of Sciences (2019), 24.8% perovskite solar cells of UNIST (2020), 15.7% organic solar cell of Y6 material from South China University of Technology and Central South University (2019), 18% organic solar cells of the Institute of Chemistry of the Chinese Academy of Sciences (2020), etc. 

The characteristics of IVS-KA6000 will be introduced in this article, especially real-time measuring and analyzing features. IVS-KA6000 can control a variety of commercial SMUs (Source Measurement Units) except basic measurement of current and voltage. User can get various important parameters of solar cells with IVS-KA6000 analyzing characteristic curve of test result. In this article, we also introduce several representative and innovative functions which are the main differences compared to the other IV software.  

The links of introduction for other functions of IVS-KA6000 are as follows: 
02. Project Management Mode: Lightweight settings and complete IV curve with one click. (Coming soon) 
03. Real-time data and file management (grasp all data information at a glance). (Coming soon) 
04. The most comprehensive parameter setting for IV characteristic (Coming soon) 
05. Integrate with a variety of hardware (Coming soon) 
06. Possess coefficient-correction-functions related to IEC standards (Coming soon) 
07. Automatic variable-light-intensity test (Coming soon) 
08. MPPT tracking function (Coming soon)  
09. IT / VT monitor (Coming soon)  
10. KA-Viewer analysis function (Coming soon) 

Introduction 

Voltage-current characteristic curve under light condition is the most important test for solar cells. Various important parameters can be obtained by analyzing voltage-current characteristic curve. These parameters are important for evaluating the quality of a solar cell, including short-circuit current, open-circuit voltage, maximum power, conversion efficiency, etc. 

History and Features of IVS-KA6000 Development 

With over 10 years of experience, voltage-current testing software, IVS-KA6000 is developed by Enli Technology. IVS-KA5000, the previous generation, has more than 500 users. IVS-KA6000 is evolved from IVS-KA5000 based on users’ feedback and experience. 

IVS-KA6000 can control a variety of SMUs. The supported brands and models are 
Keysight B29xxa Series:


Keithley 24xx Series:


Keithley 26xx Series:



IVS-KA6000 can collect current and voltage data according to the measurement settings defined by users. IVS-KA6000 can immediately analyze the relevant parameters of the device under test while completing data collection. These parameters include 
Short-Circuit Current, Isc: Measured current in the short-circuit condition. 
Short-Circuit Current Density, Jsc: Measured current density in the sort-circuit condition, where the current density is defined by current per active area. 
Open Circuit Voltage, Voc: Measured voltage in the open-circuit condition. 
Fill Factor, FF: The ratio of the actual maximum power to ideal solar cell maximum power. 
Maximum Power, Pmax: The maximum power point is at the optimum trade-off between current and voltage. The voltage at maximum power point is Vmax and the current at same point is Imax. 
Conversion Efficiency, PCE: The ratio of the maximum output power to illuminating power which is 1000 W/m2. 

The analysis formula and algorithms of IVS-KA6000 are based on the algorithm developed and released by NREL. To ensure the accuracy of analyzed results, it’s also verified by several third-party laboratories which have the solar-cell-efficiency certification. IVS-KA6000 help users to quickly get the correct evaluation of solar cells. 


▲Fig. 1 IVS-KA6000 software. Various test results can be simultaneously displayed in the window. 
IVS-KA6000 will immediately analyze the important parameters of the solar cell after getting each IV curve.



▲Fig. 2 Summary display of automatic analysis of IVS-KA6000. 


Difference between IVS-KA6000 and Other Brands 

Most of the IV testing software on the market is positioned as an accessory to the solar simulator and only provides basic test and easy analysis. Other supplier won’t develop new functions according to user’s experience and requirement. 



 
▲Fig. 3 Simple IV test software from other brands. It only provides basic IV measurement and analysis.
However, feedbacks from customer usage and requirements cannot be satisfied. For the development of new-type
solar cells, typical simple IV test software cannot support relevant measurement and analytical technology
and is hard to help user make a breakthrough.


For example, due to the hysteresis effect of perovskite solar cell, changes in voltage and electric field affect the carrier mobility and charge accumulation. This hysteresis effect makes different IV curves for the same solar cell when doing forward-voltage-sweep and reversing-voltage-sweep. 

 
▲Fig. 4 Different results of IV curve for forward and reverse scan are observed for the same perovskite solar cell. 
A significant difference between two curves represents different results of the conversion efficiency.


The IV software developed by Enli Technology is the pioneer in the industry in perovskite and organic solar cells and achieves many important functions, including: 
1.Forward and Reverse IV Scan Function 
2.Sweep Voltage Increase Rate Control 
3.I-t, V-t, MPPT Tracking Function 
4.Single Sample Multi Sub-Cell Automatic Test 

Brief introduction to these functions is described in the following content. Readers can understand the core value of IVS-KA6000 and the main difference between IVS-KA6000 and other typical IV software. 

1.Forward and Reverse IV Scan Function:  

Traditionally, individual measurement condition settings twice are necessary. Reverse IV-scan can be started until completing forward IV-scan condition settings, forward IV-scan test, and then reverse IV-scan condition settings in order. Besides, two individual IV curves need to be plotted together by manual after finishing all measurements. Traditional method is extremely time-consuming. 

Enli Technology is the first supplier of IV software to realize automatic forward and reverse IV scanning functions. In 2015, pervious generation, IVS-KA5000 has implemented these functions. Besides, more than 100 laboratories developing high-efficiency solar cells adopt IVS-KA5000 to help users to accelerate the breakthrough of conversion efficiency (PCE). 


2.Sweep-Voltage-Increase-Rate-Control:  

The voltage-increase-rate will affect the IV curve results of perovskite solar cells. Since 2016, the voltage-increase-rate-control has been a standard function of the IVS-KA software. IVS-KA software attached this control function help users to deeply analyze the material system and hysteresis effect of perovskite solar cells. 


▲Fig. 5 The IV curve results of the perovskite solar cell under different sweep-voltage-increase-rate
conditions. (Source: The Journal of Physical Chemistry Letters)


3.I-t, V-t, MPPT Tracking Function:  

To analyze the stability of new material system, ,in 2017, IVS-KA software added the “I-t Monitor” function to monitor the time-dependent current of single solar cell. Moreover, monitor functions of time-dependent voltage(V-t) and maximum-power-point-tracking (MPPT) are integrated to IVS-KA6000. It will be a convenient tool to users to study the stability of new types of solar cells such as perovskite or organic.

▲Fig. 6 Many time-tracking functions are implemented in IVS-KA6000, including I-t, V-t, and MPPT. 
IVS-KA6000 will be a powerful and convenient tool to users and researchers. (Source: Nano Energy)


4.Single Sample Multi Sub-cell Automatic Test:  

With the development of efficiency research, everyone values the authenticity and reproducibility of the improvements to solar cells with different manufacturing process. Providing statistical data on experimental results is the effective way to confirm the reality, as shown below. To get statistical data, a large number of solar cells will be tested, and generate repeated measurements. If the automatic testing for a single sample with multi-sub-cells is realized, the research and efficiency of the laboratory will be greatly improved. And thereby speeds up the publication rate of papers.

IVS-KA6000 can not only integrate the former 8-channel four-wire multiplexer manufactured by Enli Technology but also support 32-channel automatic multiplexer. It can automatically switch test for 32 independent sub-cells and greatly shorten user’s testing time without switching and reconnecting cable. Besides, it reduces the possible artificial-measurement-errors. 


▲Fig. 7 The PCE efficiency distribution of 23.3% perovskite solar cells with different manufacturing
processes published by Nature Photonics. To get this statistical distribution, two separated groups
(experiment and control) were performed IV measurements and PCE analysis. This diagram demonstrates 
the overall reproducibility of experimental results and the authenticity of the data.


Always Imitated, Never Surpassed  

With over 10 years of experience, PV Test IV software has been developed by Enli Technology. With requirements and feedbacks from more 500 customers and top laboratories, IVS-KA6000 has integrated several innovative and important test functions, especially for new types of solar cells. IVS-KA software has assisted many customers to continuously break through the record of the highest cell-conversion-efficiency and published on NREL’s best cell efficiency chart. For example, 23.3% perovskite solar cells from Chinese Academy of Sciences, 24.8% perovskite solar cells from UNIST, 15.7% organic cells of Y6 material from South China University of Technology and Central South University, 18% organic cells from Institute of Chemistry of the Chinese Academy of Sciences, etc.  




▲Fig. 8 Rough IV software imitating IVS-KA.


IVS-KA software developed by Enli Technology has been leading the development of testing technology to high-efficiency solar cell. Plagiarism is unavoidable, but we always focus on creating customer value, continue to invest in development of new technology, and continuously improve the functions of IVS-KA. We will continue to introduce related important functions in the following series of articles. Users possessing IVS-KA6000 can clearly understand the powerful functions and successfully apply to research to produce good and fast results. 

Related Products 
● IVS-KA6000 Software Products (Coming soon)
● IVS-KA-Viewer Software Products (Coming soon)
SS-X50 Solar Simulator Beyond 3A
SRC-2020 Standard Reference Cell That Meet the WPVS Global Comparison Standard

Further Reading 
02. Project Management Mode: Lightweight settings and complete IV curve with one click. (Coming soon)
03. Real-time data and file management (grasp all data information at a glance). (Coming soon) 
04. The most comprehensive parameter setting for IV characteristic (Coming soon)
05. Integrate with a variety of hardware (Coming soon) 
06. Possess coefficient-correction-functions related to IEC standards (Coming soon) 
07. Automatic variable-light-intensity test (Coming soon) 
08. MPPT tracking function (Coming soon) 
09. IT / VT monitor (Coming soon) 
10. KA-Viewer analysis function (Coming soon)