Solar Cell Characterization

Abstract

The solar cell characterizations covered in this chapter address the electrical power generating capabilities of the cell. Some of these covered characteristics pertain to the workings within the cell structure (e.g., charge carrier lifetimes), while the majority of the highlighted characteristics help establish the macro-performance of the finished solar cell (e.g., spectral response, maximum power output). Specific performance characteristics of solar cells are summarized, while the method(s) and equipment used for measuring these characteristics are emphasized.The most obvious use for solar cells is to serve as the primary building block for creating a solar module. As such, a key pursuit is to manufacture a solar module, or more correctly, to manufacture each unique model or product line of photovoltaic (PV) module, using cells that perform as similarly as possible. To achieve that end, manufacturers conduct quick measurements of mass-produced cells and then allocate them into a few groups or "bins" based on those measurements. The key cell characteristic(s) used for binning are embodied in the cell's electrical current versus voltage (I-V) relationship, Fig. 8.1. From these curves, the cell's maximum power output, short-circuit current , and open-circuit voltage, in particular, are identified.Additional cell parameters and relationships are used to more fully characterize a solar cell. These additional characteristics include, but are not limited to, spectral response, fill factor, series resistance, temperature coefficients, and quantum efficiency. Knowledge of these additional parameters is helpful, for example, when developing, evaluating, and fine tuning a new cell design and manufacturing process. Characterizations that focus on maximizing accuracy, moreover, are especially important for the purpose of creating reference cells. Reference cells serve as transfer standards that can be used by manufacturers and third-party testing

Solar energy-A look into power generation, challenges, and a solar-powered future

“…Typical error sources in the measurement of photocurrent include but are not limited to the following: Errors related to electrical instruments (I to V converter, AC voltmeter) such as noise, calibration, and offsets errors. Errors related to PV cell/module such as temperature bias, white light bias, device sensitivity and response time to light. Error related to mechanical factors such as vibrations and movement of optics. Typical error sources in the measurement of light power includes but are not limited to the following: Errors related to filament or light source as a result of intensity fluctuation and change in spectrum over age and time Calibration errors related to signal‐to‐noise and calibration drift with time. Errors related to stray light when light seen by the detector and not the cell as well as the incomplete exclusion of grating orders and pinholes in the filter. Detectors performance errors such as resolution, signal‐to‐noise, and time constant errors of pyroelectric detector. …”

Roadmap on energy harvesting materials

“…The complete procedure on how to use a calibrated reference cell to perform accurate I-V measurements traceable to a given RC has been published and is conceptually very similar to how we do I-V measurements under the SRC [97,100]. The flowcharts in figure 20 outline the steps needed for accomplishing a traceable indoor photovoltaics measurement metrology.…”

Local Tilt Optimization of Photovoltaic Solar Panels for Maximum Radiation Absorption

“…Typically, PV panels absorb in the wavelength (λ) ranging from 300 nm to 1200 nm. Figure 4 shows the spectral response of a typical silicon solar cell [22]. The dots represent experimental data adapted from Ref.…”

“…The dots represent experimental data adapted from Ref. [22]. The solid line represents a polynomial adjustment as further explained in Section 3.2.…”

“…Typical spectral response of a silicon solar cell under glass. The dots represent experimental data adapted from Ref [22]…”