Detection methods to broaden the measurable range of hydrogen peroxide (H2O2) concentrations are suggested for agricultural applications. Photovoltaic detection is based on the chemiluminescence (CL) of luminol with potassium ferricyanide as a catalyst. The use of potassium ferricyanide (non-biomaterial) enables the sensor to be stored for a long period at room temperature and can lower the manufacturing cost. In this study, the measurement range was broadened down to 3x10(-5)% by improving the stability and enhancing the sensitivity of the sensor. To improve the stability in the time domain, a low pass filter (LPF) was connected, reducing noise caused by ambient light. To enhance sensitivity, a reflective plate was employed to redirect diverging emitted light toward the photodiode. The highest possible detection level was also elevated up to 0.5% by preparing the mixture of luminol and catalysts (MLC) at high concentration. As a result, the performance index, IMR (Index of Measurable Range=maximum/minimum ratio of detectable concentration) of the system grew to over 16,000, which is about 16 times larger than previous results. All of the experimental results were confirmed to be in good agreement with calculated theoretical output voltages from chemiluminescence. The proposed device is intended to replace hazardous pesticides or antibiotics which have been used for agricultural applications.