Question

Which one of the following is NOT true for Quantum dots as fluorescent probes in fluorescence microscopy?

• A. They are highly resistant to photobleaching.
• B. They can generate fluorescence of different emission wavelengths.
• C. They are nanocrystals of different sizes.
• D. Their fluorescence properties do not depend on the size of the Quantum dots.

Hint:

Quantum dots exhibit size-dependent fluorescence due to quantum confinement effects. Smaller dots emit higher energy (blue) light, and larger dots emit lower energy (red) light.

Answer 1

The Correct Option is D

Step 1: Understand the properties of Quantum dots
Quantum dots are semiconductor nanocrystals whose optical properties are strongly dependent on their size and shape. Smaller quantum dots emit shorter wavelengths (bluer light), while larger dots emit longer wavelengths (redder light).
Step 2: Eliminate the correct statements
(1) is true: Quantum dots are known for their excellent resistance to photobleaching.
(2) is true: Due to their tunable band gaps, quantum dots can emit different wavelengths depending on size.
(3) is true: Quantum dots are indeed nanocrystals of varying sizes.
Step 3: Identify the incorrect statement
(4) is NOT true: The fluorescence properties of quantum dots do depend on their size, which directly affects their emission wavelength.