I thik u can use digital light meter for measuring the intensity of visible light

What light source are you using? The type you are using is very important because many have uneven outputs across the spectrum, for example a mercury arc has several spikes in the near UV and green regions whereas the xenon arc has a broad and more even output in the visible but several large peaks in the NIR. There are many kinds, the most common for visible light (solar simulator types) is the xenon arc. I suspect you have a mercury arc lamp which probably isn't the best for visible solar simulation for the afore-mentioned reasons, it is however pretty good for solar UV where the photocatalyst activity isn't too sensitive to large variations in intensity with wavelength (e.g. for TiO2).

Thank you for your kind reply. I am using Light emitting diode array as the visible light source. Pls find the attachment reg the emission spectrum of the warm white LED array i am using.

Thank you for your kind reply. I am using Light emitting diode array as the visible light source. Pls find the attachment reg the emission spectrum of the warm white LED array i am using

The best is to use a radiometer which give light intensity at the different wavelengths within the wavelength range.

For accurate light intensity measurement, you have to use digital power intensity meter (You may check the power intensity meter available from Newport corporation http://search.newport.com/i/1/x1/pageType/q1/Products/q2/Laser%20Measurement%20%2526%20Control/q3/Optical%20Power%20%2526%20Energy%20Meters/x2/section/x3/chapter/nav/1/)

You have to consider the geometry of the system reactor-light, the emission spectrum and value of quantum yield of the actinometer for all wavelenght emmited by your light source. Similar calcula were carried out by Alberto Cassano and Orlando Alfano. You can combine the authors' name with 'actinometry" with attetion to the geometry of the system. I think you will be able to find what you need.

Hello, as other colleguas already suggested you have to think about the emitted spectrum of your light source. You can´t simply use any kind of powermeter as it is not calibrated to your light source. The best way is to get low cost fibre optic UV/VIS spectrometer (e.g. ocean optics, LOT Oriel etc.). These spectrometers allow both wavelength and absolute power calibration. Additionally they are very simple to use as the use optical fibres. In other words, you can very easy measure directly at your sample position and don´t have to worry about geometry.

Here is a example:

http://www.spectroscopytips.com/apps/testing-the-stability-of-polymeric-semiconductor-materials/

I would not suggest to use actinometry in order to probe absolute intensity of a multiwavlength light source as you then need the wavlenght resolved quantum efficiency. This a hardly availabe to my knowledge.

Try to download the following papers, may be useful:

- The extended use of actinometry in the interpretation of photochemical reaction engineering data - Zalazar, Labas, Martin, Brandi, Alfano and Cassano;

- actinometry in the interpretation of photochemical reaction engineering data - zalazar and cassano;

- Photocatalysis in water environments using artificial and solar light - O. Alfano, D. Bahnemannb, A.E. Cassano, R. Dillert, R. Goslich

Thank you all for your valuable advice. I shall measure fluence rate using Ophir PD100 Nova II power meter

Thank you Damián Monllor-Satoca

@Gokulakrishnan Subramanian, can you please share the details of Ophir PD100 Nova II power meter, can we measure natural sunlight intensity also?

For natural sunlight measurements go for meco solar power meter