LED Light Sources:

The EvoluChem™ LED spotlights are designed specifically for photo-catalytic chemistry applications. They fit the photoredox box and they are designed to irradiate all samples with maximum efficiency. The LED chips are selected for specific wavelengths 365 nm, 405 nm, 425 nm, 455 nm, 475 nm, 525 nm, 6200K white.

Light Power vs Irradiance

Although the total power of LED light is important, it is essential to estimate the amount of light that actually goes on the sample. If the light is spread over a large area the density of light (irradiance) on sample will be little. Therefore we designed the EvoluChemTM LEDs to focus the light toward the samples. They have light beam angle of  25° which allows to obtain better light efficiency than the Kessil light (40°).

With a more focused beam the Evoluchem LED 18W average irradiance is 50% higher than a 34W Kessil light.

 

Light Sources	Electric Power (W)	Total Irradiance* (mW/cm2)
Kessil 150N	34W	22
P201-18-2 450-455 nm	18W	34
P303-30-1 450-455 nm	30W	55

 

Experimental Details:
In duplicate in a 4-ml vial equipped with a teflon septa and 2×7 mm stir bar, were weighed 4-bromoacetophenone (4.95 mg, 25 µmol) and potassium benzyltrifluoroborate (4.50 mg, 25 µmol, 1 equiv.). To this vial was added a 1.0 ml solution in DMA containing NiCl2-dme (1.1 mg, 5 µmol, 20 mol %), dtbbpy (1.3 mg, 5 µmol, 20 mol %) and Ir(dF-CF3-ppy)2(dtbpy) (1.12 mg, 1 µmol, 4 mol %) followed by addition of 2,6-lutidine (17.5 µl, 150 µmol, 6 equiv.) . The solution was sparged with nitrogen via submerged needle for 5 minutes and vial was placed in EvoluChem photoreactor with blue Kessil 34W LED or with a EvoluChem LED 18W 450-455 nm. Reaction time course was monitored at 0, 5, 15, 45, 120, 240, and 360 minutes.  

 

Light Spectrum
EvoluChem  LED 30WHCK1012-01-008  

 

EvoluChem  LED 18W

 

Light Sources	Wavelength	LED	Relative Irradiance*	Part Number
P205-18-1 365 nm 18W	365 nm	LG/CREE	9 mW/cm2	HCK1012-01-011
P205-18-1 380 nm 18W	380 nm	LG	8 mW/cm2	HCK1012-01-013
P206-18-1 405 nm 18W	405 nm	LG	28 mW/cm2	HCK1012-01-010
P207-18-1 425 nm 18W	425 nm	EPILED	33 mW/cm2	HCK1012-01-012
P201-18-2 450 nm 18W	450 nm	CREE XPE	34 mW/cm2	HCK1012-01-002
P202-18-1 475 nm 18W	475 nm	CREE XPE	23 mW/cm2	HCK1012-01-003
P203-18-1 525 nm 18W	525 nm	CREE XPE	10 mW/cm2	HCK1012-01-004
P204-18-1 6200K 18W	Cold White	CREE XTE	29 mW/cm2	HCK1012-01-005
P303-30-1 450 nm 30W	450 nm	CREE XPE	55 mW/cm2	HCK1012-01-008
P301-30-1 365 nm 30W	365 nm	LG	25 mW/cm2	HCK1012-01-006

*Average relative irradiance is measured in the photoredox box.